Other electronic media - General introduction to citation practices - Part II. Source Citation

A manual for writers of research papers, theses, and dissertations, 7th edition - Kate L. Turabian 2007

Other electronic media
General introduction to citation practices
Part II. Source Citation

Sources available in other electronic media, such as CD-ROMs, are more stable than those posted online. Those that are reproduced and distributed in quantity should be cited similarly to published books, with the addition of information about the medium; see 17.5.8 (for bibliography style) or 19.5.8 (for reference list style).

If a source is available in more than one electronic medium (for example, online and on CD-ROM), or both electronically and in print form, consult the most stable version, and always cite the version you consulted.