• Electronic sources are of two types--those that change (such as a Website or a regularly updated on-line resource) and those that do not (such as a computer program or a portable database stored on a CD-ROM). It is essential to provide the date of your access to a source that may have been subsequently updated. If you are uncertain about what kind of source you are using, give the date you viewed it.
• Information on the Web can be reached by many different routes, and often the links provide significant context to the information. For example, you may be using the facts on toxic substances from a Website that you reached from a link at an especially interesting Website on the environment. The title of the environmental Website adds depth to your report.
• Mailing lists use different addresses: the posting address (where the article first appeared) and the retrieval address (where the reader of your paper would have to go to read the article). You will need to list both.

The most important guideline is that the reader of your paper should be able to find your source, or if it's a source that may have been modified (or deleted), that you identify the date of your reading.

Note that you may have found most of your sources of information electronically, but you probably read most of them in print. Printed sources will be presented according to the existing guidelines for your discipline. Unless told to do so, do not separate your sources by type (books, articles, e-mail, CD-ROMs, etc.).

The format described in the linked document below represents the consensus of the scholars publishing on the topic of documentation style as of June 1996. Some of the specifics have yet to be officially endorsed by the dominant organizations, but this format does not violate existing rules, merely adds to them. See References.