14: Documentation I: Notes and Bibliography

Chapter Contents» Source Citations: An Overview» Considerations for Electronic Sources

14.10Publications available in more than one medium

In many cases the contents of the print and electronic forms of the same publication are intended to be identical. Moreover, publishers are encouraged to note explicitly any differences between the two (see 1.73). In practice, because there is always the potential for differences, intentional or otherwise, authors should cite the version consulted. Chicago recommends including a URL or DOI to indicate that a work was consulted online; for other nonprint items, the medium should be indicated (e.g., CD-ROM). Note, however, that alternate electronic formats offered by a single publisher from the same websitefor example, PDF and HTML versions of the journal article mentioned in 14.6do not constitute separate sources. The URL for each such version will generally differ, but the DOI will not. In fact, a DOI serves readers by pointing to each medium in which a work is published. (Though a print source may list a DOI, authors need not record it as part of their research unless their publisher or discipline requires it.)