While information on standard types of references can be found in the sources listed above, here are a selection of electronic reference formats that can be harder to find.
Journal article on the Internet: Abood S. Quality improvement initiative in nursing homes: the ANA acts in an advisory role. Am J Nurs. 2002 Jun [cited 2002 Aug 12];102(6). Available from: http://www.nursingworld.org/AJN/2002/june/Wawatch.htmArticle
Article with document number in place of traditional pagination: Williams JS, Brown SM, Conlin PR. Videos in clinical medicine. Blood-pressure measurement. N Engl J Med. 2009 Jan 29;360(5):e6. PubMed PMID: 19179309.
Article with a Digital Object Identifier (DOI): Zhang M, Holman CD, Price SD, Sanfilippo FM, Preen DB, Bulsara MK. Comorbidity and repeat admission to hospital for adverse drug reactions in older adults: retrospective cohort study. BMJ. 2009 Jan 7;338:a2752. doi: 10.1136/bmj.a2752. PubMed PMID: 19129307; PubMed Central PMCID: PMC2615549.
Pamphlet/brochure: Barker B, Degenhardt L. Accidental drug-induced deaths in Australia 1997-2001. Sydney (Australia): University of New South Wales, National Drug and Alcohol Research Centre; 2003. 6 p.
Letter or email: Reed, Walter (Army Medical Museum, Washington, DC). Letter to: W.S. Halstead (Johns Hopkins Hospital, Baltimore, MD). 1985 Apr 10.
Web site: Cancer-Pain.org [Internet]. New York: Association of Cancer Online Resources, Inc.; c2000-01 [updated 2002 May 16; cited 2002 Jul 9]. Available from: http://cancer-pain.org/.
Part of a web site: American Medical Association [Internet]. Chicago: The Association; c1995-2002 [updated 2001 Aug 23; cited 2002 Aug 12]. AMA Office of Group Practice Liaison; [about 2 screens]. Available from: http://www.ama-assn.org/ama/pub/category/1736.html
Database on the Internet: Who's Certified [Internet]. Evanston (IL): The American Board of Medical Specialists. c2000 - [cited 2001 Mar 8]. Available from: http://www.abms.org/newsearch.asp