I know of at least 2 works which discuss the citation of electronic
works:

Li, Xia and Crane, Nancy B.   Electronic style: a guide to citing
  electronic information.  Westport, Ct. : Meckler, 1993.  xi, 65 p.

Patrias, Karen.  National Library of Medicine recommended formats
  for bibliographic citation.  Bethesda, Md. : National Library of
  Medicine, Reference Section, 1991.  248 p.

  Chapter XII, Sections C (serials in electronic formats), E (bulletin
   boards), and F (Electronic mail)  have been reprinted in:
   Strangelove, Michael and Kovacs, Diane.  Directory of electronic
   journals, newsletters, and academic discussion lists; edited by
   Ann Okerson.  3d ed.  Washington, D.C. : Association of Research
   Libraries, 1993.  pp. 13-26.

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