Network Working Group J. Max Request for Comments: 2150 W. Stickle FYI: 31 Rainfarm Category: Informational October 1997 Humanities and Arts: Sharing Center Stage on the Internet Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Abstract This document is designed primarily for individuals who have limited knowledge of, or experience with, the Internet. The purpose of this document is to provide members of the Arts and Humanities communities with an introduction to the Internet as a valuable tool, resource, and medium for the creation, presentation, and preservation of Arts and Humanities-based content. The intended audience is practicing artists, scholars, related professionals, and others whose knowledge, expertise and support is important to ensuring that the Arts and Humanities are well-placed in the global information infrastructure. Table of Contents 1. Introduction............................................... 3 1.1 Definition of Arts and Humanities......................... 3 2. What does the Internet mean to the "Artist?"............... 4 2.1 Access to the Global Community............................ 5 2.2 Sharing Your Work and Collaborating with Others........... 6 2.3 Freely Available Software, and Other Information.......... 8 3. What is the Internet?...................................... 8 3.1 What is the World Wide Web?............................... 9 4. How does the Internet Work?................................ 10 4.1 Internet Addresses........................................ 11 4.1.1 Computer Addresses and Hostnames......................... 12 4.1.2 Addresses of People on the Internet...................... 12 4.1.3 Information Addresses, Locators, URLs.................... 13 4.2 How Does the World Wide Web Work?......................... 14
4.3 Other, Higher Level Protocols on the Internet............. 15 5. Forums..................................................... 16 5.1 Message Based Communications.............................. 16 5.1.1 Electronic Mail - email.................................. 17 5.1.2 Newsgroups............................................... 17 5.1.3 Electronic Bulletin Board System - BBS .................. 18 5.2 Real-Time Communications.................................. 19 5.2.1 Chat - IRC............................................... 19 5.2.2 Multicasting............................................. 20 5.2.3 MUD - Multi-User Dungeon................................. 20 5.2.4 Audio/Video Conferencing................................. 21 5.3 Archives.................................................. 22 5.3.1 Searching................................................ 22 6. Accessing the Internet..................................... 25 6.1 Internet Service Providers................................ 26 6.2 Computer Hardware and Software Tools...................... 26 6.3 Multimedia................................................ 31 7. Creating Content........................................... 32 7.1 Getting Help.............................................. 33 7.2 About File Formats........................................ 34 7.3 Creating Text and Hypertext Documents..................... 35 7.4 Creating Graphic and Moving Images........................ 35 7.4.1 Bitmap Image Formats..................................... 36 7.4.2 Vector Image Formats..................................... 37 7.4.3 Video Formats............................................ 37 7.5 Creating Music and Sound Files............................ 38 7.6 Content Design Issues..................................... 40 7.7 Publicizing Your Work..................................... 41 8. Issues and Challenges...................................... 42 8.1 Security Issues........................................... 43 8.2 Viruses................................................... 44 8.3 The Standard Disclaimer................................... 44 8.4 Copyrights and Intellectual Property Issues............... 45 8.4.1 Copyright................................................ 45 8.4.2 Trademark................................................ 46 8.4.3 Privacy.................................................. 47 8.4.4 Seek Professional Advice................................. 47 8.5 Conducting Business over the Internet..................... 47 8.6 Netiquette................................................ 48 9. Glossary................................................... 49 10. Resources, References, etc................................. 51 10.1 RFCs and Internet-Drafts.................................. 51
10.2 Internet Documents........................................ 52 10.3 Other Sources............................................. 53 10.4 Freely Available Web Browser Software..................... 54 10.5 The Internet Assigned Numbers Authority................... 54 11. Security Considerations.................................... 55 11.1 Formulate a security policy............................... 55 11.1.1 Talk to your Internet Service Provider................... 56 11.1.2 Make sure your systems are up to date.................... 56 11.1.3 Use the tools available.................................. 56 12. Acknowledgments............................................ 57 13. Authors' Addresses......................................... 57 Appendix A. Internet Projects of Interest to the Arts and Humanities Communities..................... 58 Appendix B. Starting Points; A brief list of related sites...... 60 Appendix C. Examples for using the RFC server RFC-INFO@ISI.EDU.. 62 1. Introduction This document has been structured to provide information about, and examples of, the wide range of functions and capabilities available on the Internet today. It is intended to illustrate the potential of current networking technologies for personal and cultural growth. Some basic functions of the Internet are described, along with their applications and forums for building online communities of interest, such as the World Wide Web, Email, and Network News. This is followed by discussion and examples of hardware and software being used to support the creation and presentation of artistic and literary works, along with examples of how Arts and Humanities content is being represented, stored, and retrieved on the Internet. In addition to illustrating the great potential of the Internet, this document provides a brief introduction to the issues and challenges that affect the development and presentation of Arts and Humanities content online, such as privacy and property rights. Included is a brief Glossary, and a number of Appedices which provide pointers to other sources of information about the Internet. 1.1 Definitions of Arts and Humanities For purposes of this document the term "Arts" includes, but is not limited to, dance, design arts, folk arts, literary arts, media and film arts, music, theater, and visual arts.
The term "Humanities" includes, but is not limited to, the study of the following: language, both modern and classical; linguistics; literature; history; jurisprudence philosophy; archaeology; comparative religion; ethics; the history, criticism and theory of the arts; those aspects of social sciences which have humanistic content and employ humanistic methods; and the study and application of the humanities to the human environment. For purposes of simplicity this document will use the word "Artist" to mean both Artist and Humanist: "all practitioners who work in the fields of the visual, performance, and literary arts, as well as museum curators, librarians, and others who are involved in the research, restoration, and presentation of that which comprises our cultural heritage." 2. What does the Internet mean to the Artist? The Internet is exerting a profound influence on our society. Even now in its infancy, the effects of the Internet can be easily seen in popular media as well as in the way we do business. But the most dramatic influences are in the children who are now growing up with the net. Many parents are aware of the influence television has over their children. With the advent of WEB-TV, the Internet has begun to assimilate Television, transforming it into something more powerful. This coming integration of information, communication and entertainment will play a major role in teaching and shaping the minds of those who live and grow up with it. Because of this power, it is critical that the best parts of human culture are represented on the Internet. If we raise the Internet right, it will return the favor by nurturing a generation that may well grow up wiser than ourselves. This is where artists are needed. Because the net is primarily built and run by Scientists and Engineers who are creatures of mind, it is the heart and soul of the Internet that is weak. Artists are the heart and soul of human culture, and must bring the fruits of their efforts to the net to give the net culture, and future generations their essence of humanity. If that does not convince you, we will also introduce you to some of the many tools artists may use to exploit the net for their own personal gain. As the online culture becomes a more balanced representation of humanity, the net will become an essential tool for collaboration, communication, and distribution of art and humanities content. The day is coming where those who are not on the net will be greatly handicapped in the expression and distribution of their works.
The net is the new frontier for the growth of humanity. Can you afford not to be involved? 2.1 Access to the Global Community In the past, artist's audiences and collaborators were limited to the people around them. Improvements in transportation and communication have allowed these associations to expand, but even today few members of the artistic community have gone global. The Internet changes all this by allowing anyone access to a global community. A great many arts institutions and organizations have now established sites on the World Wide Web and a significant number of online discussion groups focus on the arts and humanities. Consortiums of museums and libraries are now using networking technologies to support research and projects involving more effective ways to collect, store, and disseminate objects of antiquity and other non- textual primary sources, as well as textual sources. Sites are also created by individuals and for institutions, organizations, and businesses for reasons ranging from commerce to simple self-expression. The Internet connects hundreds of countries, thousands of cities, and countless groups and individuals around the globe. On the Internet today you can find information on topics ranging from art and music to guns and ammunition; among which are astronomy, news, astrology, agriculture, acupuncture, botany, biology, zoology, food, psychology, medicine, space exploration, genetics, media, chemistry, microbreweries, aeronautics, scuba diving, meteorology, neurology, artificial intelligence, mathematics, literature, wine tasting, law, painting, photography, dance, history, social sciences, politics, crafts, clothing, economics, genealogy, pets, sports, languages, dictionaries, encyclopedias, technical manuals, schools, shops, entertainment, furniture, flowers, software, hardware, computers and the Internet, just to name a few. Whatever your work requires, whatever your whim desires, you can find it on the net. People all around the world will be looking for what they want on the net, and if you have what they want, then through the magic of the Internet, you are their next door neighbor. With access to the Internet, the world is at your fingertips. Bring your questions on health, the environment, government, and religion, and look though volumes of documentation on your concerns, or discuss your questions with others electronically. Once you get used to it, you will even be downloading more information and tools to assist you further.
The Internet provides a forum in which diverse cultures can merge, and allows people to visit faraway places from the privacy and safety of their own computer. The Internet explorer will also find that many sites are multilingual. Once you have the basic tools for using the Internet you will begin to understand how easy, helpful, informative, and exciting it can be. With a few quick strokes you have accessed a great library, museum, or gallery, toured a faraway city, or looked up an old friend. You might find an out of print book you have always wanted, then either read it on your computer screen, or print it out on your printer. If you do not have a printer, simply save it to your floppy disk and bring that to a printshop or friend with a printer. It really is that easy. You could spend the afternoon at the Smithsonian, or the Louvre without ever leaving your chair. For a more athletic adventure, you could put your computer in front of your treadmill, and jog through the online Olympics site. When you are ready, you can explore deeper. Follow other links to smaller sites, lesser known writers, artists, poets, and thinkers, and discover the emerging world they are creating. With the proper tools you can even view moving pictures, and listen to music and other audio. Perhaps you would like to locate a rare album, or debate one musicians merit over anothers. Perhaps you prefer to discuss and compare the works of others with producers, collectors, gallery owners or other professionals in your field, or related fields. You might want to find out who's hot and why. You could also find out where, and when shows, showings, benefits, conferences, releases, signings, and performances are taking place, or announce your own. They say that for every artist, there is a critic, and you could meet one, or be one, on the Internet. 2.2 Sharing Your Work and Collaborating with Others Artists often want to share their work with other artists so that they can get peer comments and recognition. The Internet is a great place to explore new ideas with other artists as well. Perhaps you are a painter who has developed a method for keeping acrylics moist during long sessions, or a photographer who has discovered a new lighting technique. You could make the information available over the Internet to enlighten others, or to get their feedback.
Perhaps you've had difficulty in some aspect of your work, and you'd like to talk to others who have had similar experiences to find out how they solved them. There are many types of content that artists can share. Including: - text: stories, poetry, historic accounts, transcripts, etc. - images of their visual work: paintings, photographs, sculpture, etc. - images of themselves: photographs, self-portraits, etc. - sound files of their audio works or voice presentations of their works: books on tape, speeches, tutorials, music, etc. - moving pictures: video arts, performance arts, etc. - a description of their art process and works of art - resumes and biographical data - contact information in the form of electronic mail address, postal mail address, phone, etc. Electronic mail is most popular because it allows people to respond spontaneously. After you've met some of the global critics, and compared your work with others, you may feel so bold as to share your work with others. Perhaps emailing a manuscript to a publisher, or putting up scans of your art will entice a buyer. Perhaps it will entice a critic to say wonderful things about your work. Perhaps putting your work on the Internet will bring fortune and fame, or perhaps it will encourage others to put their work up. Increasing the cultural content of the Internet will have profound results in all areas of the Arts. There are many ways of collaborating over the Internet. As mentioned in previous sections it is easy to see how to communicate and exchange work with other artists from anywhere in the world. In addition, there are art and literature projects which explore the Internet by asking people to submit their feelings, thoughts, and ideas through the Internet. Some of these projects will allow interested people to come to them, others may be distributed in various ways to actively seek out people interested in participation. There are also games which are played over the Internet, by players all over the planet. These types of games, which are described in greater detail in Section 5, can be both entertaining and educational. Some games offer players the opportunity to alter the environment, so that ideas and information contained in the game evolve over time into a jointly constructed experience.
2.3 Freely Available Software, and Other Information There is a world of useful software available to you via the Internet. Known as Shareware, Public Domain, or Freely Copyable, you can find many software programs you may download and use on your own machine, often completely free, occasionally for a small and/or optional fee which helps the author to afford to create more software for general use. There are also libraries, stores, and news groups you can peruse in search of just the tool or information you want. As you explore the Internet, you will begin to find information that is beyond your reach without the right tools for viewing, listening, etc. For example, someone may have put up a sound file using a format which cannot be recognized by the software you have installed. In these cases, that person will often have included a pointer to the exact tool necessary to recognize their format, or convert the format, and you can download, install, and use this tool right away. More information on file formats is provided throughout the document. Using the basic tools acquired to access the Internet, you can begin to add to your collection software tools, both for accessing the information already on the Internet, and for creating your own content. After reading this document you will have the tools necessary to find and use this information. Appendix B provides a list of Internet sites, where communication about the arts, and freely copyable software tools and art, among other things, can be found. There are many people both like, and unlike, yourself with whom you can meet, communicate, and share ideas. Some like to just talk, you can listen if you like. Others like to just listen, so you and others can talk. There are also many forms that communication can take, from private electronic mail, to group video conferencing, to moderated newsgroups, to public bulletin boards. See Section 5 for additional information on Electronic Forums. 3. What is the Internet? As new users, the first question that probably comes to mind is: "What is the Internet?" A good answer is: "People, computers and information electronically linked around the world by a common protocol for communicating with each other."
The Advanced Research Projects Agency (ARPA) was founded in the late 1960s. Among its many projects, ARPA created a network of computers called the ARPANET. As other networks were created, most were connected to the ARPANET, and the resulting network that interconnected many networks was named, "The Internet". At last count, this "Information Superhighway" connects several million computers and over 40 million users from all over the world. The Internet should not be confused with America OnLine (AOL), CompuServe, Prodigy, and other type service providers, which may use their own, often proprietary protocols and are sites unto themselves but may also have connections to the Internet. The Internet should also not be confused with the World Wide Web which is the topic of the next section. 3.1 What is the World Wide Web? The World Wide Web, generally referred to as simply, The Web, is comprised of a subset of the computers on the Internet. You can visualize the World Wide Web as a giant magazine stand with a vast web of strings connecting various words pictures and ideas. Like a magazine rack, you may quickly select a chosen magazine, or you may browse, following the strings from magazine to magazine. More formally, the Web is vast multimedia "document" distributed among a large number of the computers on the Internet. There is no central hierarchy that organizes the Web. Instead, the information is distributed among many "Web Sites" created and used by the many people on the Internet. Each Web Site is much like a magazine in that it has a Cover Page, called the Home Page, and other pages of related information that can be connected in whatever way the author wishes. This "document" is in a format called "hypertext" which allows information in the web to be linked by words or pictures viewed on the computer. The Web is broken up into a large set of pages, called "Web Pages", of information connected by hypertext "links" which let you click on a highlighted word or picture to call up a page of related information. This is what differentiates hyper-text from "normal" text. In "normal" text, each idea, sentence or paragraph is connected in a sequence or "train of thought", from beginning to end. In hypertext however, tracks of ideas branch out through "Links", so that each idea may be connected to many different "trains of thought". This ability to follow an idea to many different destinations allows you to read hypertext documents in a way more naturally resembling human thought.
For example, you might create a "Cool Music" Web Page and place it on a "Web Server", which is any computer somewhere on the Internet running the software needed to provide access to the resident Web Pages. Anyone on the Internet could then use a piece of software called a "Web Browser" to ask the Web Server to view your Home Page. This Home Page could be a striking artwork featuring a list of your favorite albums and a few labeled buttons. While your music plays from their speakers they might choose to click on any album that catches their eye, or go to lists of information sorted by Artist, Label, or Genre. Once they get to the page for a particular album, they might see the artwork, a song list, and other links to follow. Clicking on a song might pull up the song lyrics, or perhaps even download the song. Or they could follow a link you provided from your page to the HomePage of the artists record company, or to a magazine interview of the band. If the information is out there, your page could link to it. At last check there were hundreds of thousands of web sites, home pages, and hosts on the Web. The contents of those sites are almost as varied. Some pages are personal pages containing photos of family members, lists of hobbies, or the sharing of collections such as song lyrics. Some pages are strictly business, selling everything from abalone to zymoscopes. Still other pages provide services such as information searches, and weather reports. Human culture is based on communication, and the widespread availability of information and the thought-like constructions of hypertext are the most powerful new ideas in communication since the invention of writing. A glance back at history will easily show how written language has shaped our societies. These results are only a foreshadowing of the things to come. 4. How Does the Internet Work? While it is not necessary to understand how the Internet works in order to use it, a brief technical overview will introduce you to some concepts and terms that will be used in the sections ahead. As we go into more detail here, we are assuming that you, the reader, have at least a passing familiarity with computers. Section 6.2 provides more information on computer hardware and software. On one level, networks are built out of wires, phone lines, and other pieces of hardware, and the Internet is indeed built of all these things. The essence of the Internet however is built out of an idea called the Internet Protocol.
There are many different kinds of computers. Most of them work by encoding information into ones and zeroes, which they can manipulate at incredible speeds. Unfortunately, there are many different ways of encoding information. Computers that use different methods can be said to speak different languages. In order for computers to talk to each other there must be a thing called a "Communication Protocol" that provides a set of procedures for talking and a common language to use. The Internet Protocol, or IP, is the Communication Protocol that all computers on the Internet must use and understand. It allows computers to find each other, and to send packages, or "packets", of information back and forth. Much like the Postal service reads your country code, city code, etc., but not the contents of your letter, the Internet Protocol does not care what is inside most of these packets of information. This is a great thing because it means that other, higher level protocols may transmit any possible kind of information simply by stuffing it into a packet and handing it off to the software responsible for speaking IP. Another important protocol upon which the Internet is built is the Transmission Control Protocol, or TCP. IP by itself provides a way of sending a message to another computer, but no guarantee that it will get through. Since reliable communication is a necessity, the TCP protocol was invented which uses IP to send packets and guarantees their delivery by requiring the receiver to acknowledge the information received. TCP and IP form the heart of a group of protocols aptly named the TCP/IP protocol suite. This suite of protocols provides most of the functionality of the Internet. We will be mentioning these protocols throughout the rest of the document. Information on IP and other Internet Protocols can be obtained through the resources referenced in Section 10. 4.1 Internet Addresses There are many things we would like to be able to find on the net, including people, information, and the computers themselves. An important part of IP and other protocols is the way they label things so that the computers can find and identify them. The U.S. Post Office finds people by their Postal Address, which is just a label containing information about who you are, and where you live. Likewise, the various protocols of the Internet have given computers, people, and information, addresses which can be used to find them. The following sections will describe several different kinds of addresses.
4.1.1 Computer Addresses and Hostnames When speaking IP, computers locate each other using a thing called their IP Address. Each computer on the Internet must have a unique IP Address. Some programs allow or require you to use the IP Address directly, if so, it will appear as four groups of numbers separated by dots. (i.e., 123.123.123.123) Most of the time though, you will not need to worry about the actual IP Address number, because all computers have a "Host Name" to which the number is mapped. A computers hostname also comes in parts, separated by dots. The first part is the name of the machine, and the second part is the name of the "domain" in which that computer is registered. For example, if I had a machine named "foo" registered in the commercial domain known as "com", my machine's hostname would be "foo.com". When speaking out loud, this machine's address would be spoken as "foo dot com". A domain is just an abstract category to which machines and networks may be registered into in order to organize them. Domains are organized in a hierarchy of top level domains and their subdomains. Top Level Domains include, .edu for educational institutions .gov for government sites .com for commercial companies .org for other organizations .net for network infrastructure sites .us for sites in the United States .ca for sites in Canada .nl for sites in the Netherlands .jp for sites in Japan to name a few. Domain names may be further subdivided by inserting one or more subdomain names before the top level domain, still separating everything with dots. For example, "law.harvard.edu", for the Law School at Harvard University, and "la.ca.us" for computers in Los Angeles, California in the United States. More information about the Domain Naming System can be found in the documents referenced in Section 10. 4.1.2 Addresses of People on the Internet Every human being has a given name, or full name with which we address them. When you begin to use a computer, you will be introduced to your "username". Your username, sometimes called your
user i.d., may be your initials, your last name and first initial, your nickname, a number, or anything else that is just normal letter or number characters. (Your username usually cannot contain "special" characters such as "&", or "%".) Sometimes you get to choose your own username, and sometimes your service provider or system administrator will choose one for you. Your username is used when you connect to other computers, and to identify you in electronic mail. Your electronic mail, or Email Address, will consist of your username followed by the symbol "@", followed by your computers hostname. So, for Joe Cool, who has the username "jcool", and gets his Internet service from Dirigible Online, his email address might be "jcool@dirigible.com". When spoken out loud, the "@" symbol is pronounced simply "at" so this would typically be spoken as "jcool at dirigible dot com". Email is moved around on the Internet using the Simple Mail Transfer Protocol, SMTP, over IP. Information on SMTP can be found in the documents listed in Section 10. 4.1.3 Information Addresses, Uniform Resource Locators, or URLs. In order to retrieve information from the Internet, you need to be able to find it and know how to ask for it. This is the job of the Uniform Resource Locator, or URL which functions as an address for information. Every file or document intended to be accessible through the Internet has a URL. URLs (or simplified versions of them) are now appearing frequently in TV, billboard, and magazine advertising as a company's Internet Address; basically the hostname of their web site. In previous sections we've identified IP Addresses, hostnames and email addresses; a URL contains more information. Not only does it tell you what the information is, and where to find it, it also tells you precisely which protocol you need to use to retrieve it. A URL is a machine readable, and hence somewhat cryptic, text string, in a form such as "http://www.something.com/location/filename.ext". This string can be broken down into the following pieces. http is the name of the communications protocol which can be used to access the information. In this case, it identifies the HyperText Transfer Protocol, which is used in the World Wide Web, and will be described later. Other protocols are described in Section 4.3.
: separates the protocol from the hostname // indicates that what is to follow is the hostname www.something.com is the hostname of the computer on which the document resides. In this case, the "www" indicates that it is a machine named for the fact that it is running a World Wide Web server. "something.com" is the domain in which that server is registered. Typically the "something" part is the name of the organization running the server. / separates the hostname from directory on the machine in which the information resides. location is the location of the information on the machine something.com. filename is the first part of the file name of the information you are retrieving. . a dot separates the filename from its extension ext the extension, or file "type" actually says a great deal about the file, how to handle it, and how to present it. The URLs you see will usually be simpler than this. The people at something.com assume you are going to use a modern web browser to access the information, so they may leave off the protocol information, "http://", because this is probably your web browsers default protocol. Also, if they configure their server to have a default homepage to display, they can leave off everything after the hostname part of the URL. This puts it into the form that is most commonly seen, www.something.com. URLs can specify any file and most protocols. In this example, the URL is using the protocol for moving HyperText, the HyperText Transfer Protocol, HTTP, over IP. More information on HyperText and HTTP can be found in the next section, and in the Resources section. 4.2 How Does the World Wide Web Work? Web pages are computer files written in a format called HTML, the HyperText Markup Language. HTML is the protocol for putting specific strings of letters and symbols (such as parentheses) into an ordinary
text document which can specify that words link to other pages, or be viewed in a particular type font, or display images, or many other things when viewed with the appropriate software. The appropriate software would generally be a web browser. More information about software tools is provided in Section 6.2. HTML is simple enough that most people can learn to use it, but rich enough in possibility that there will always be a thriving community of people making web pages for others. Links within a hypertext documented are implemented using references to the URL of the information to be linked to. In order to download information from distant places in the web, your computer will typically be using a protocol called HTTP, the HyperText Transfer Protocol. HTTP was designed to allow web browser software to connect to web server software on other machines and request the transmission of a web page in the form of an HTML document and any associated images, audio, video, etc. The latest version of the HTTP can actually tell what type of browser is connecting and the server is now able to better customize its default homepage to its audience. More information on HTML, HTTP, and hypertext can be found in Section 7.3, and through the references listed in the Resources section. 4.3 Other Higher Level Protocols on the Internet. There are many other higher level protocols built on top of IP. We've provide examples throughout the document, but we'll mention a few here to make you more familiar with them. telnet: a protocol for providing remote terminal service. Telnet software allows you to log in to remote computers across the net by giving you a virtual terminal on that computer. ftp: the File Transfer Protocol. FTP allows diverse machines to send simple files back and forth. FTP is usually used by archive sites to allow multiple users to download files simultaneously. smtp: the Simple Mail Transfer Protocol. The SMTP specification allows electronic mail to be sent, stored, and forwarded, around the Internet. SMTP does not specify how a mail "reader" operates, just the transmission of email.
nntp: the Network News Transfer Protocol. NNTP specifies how Internet News is passed, stored and forwarded around the Internet. gopher: the Gopher protocol creates linkages, much like the web, which is called, "gopherspace". The specification allows a gopher server to serve files in a text rather than graphic format. Many other protocols function on the Internet, and are specified in technical documents, such as are referenced in the Resources section.