To cite an article, there are a couple of different patterns you can follow, depending on how you've chosen to do your in-text citations:
If your in-text citations follow the superscript numeral system, you can cite articles like this:
Author AA. Title of article. Title of Journal [abbreviated]. Year of article;volume(issue);page numbers.
Tormey CA, Stack G. Limiting the extent of a delayed hemolytic transfusion reaction with automated red blood cell exchange. Arch Pathol Lab Med. 2013;137(6):861-864.
If your in-text citations follow the name-year system, you can cite articles like this:
Author AA. Year of article. Title of article. Title of Journal [abbreviated]. Volume(issue);page numbers.
Tormey CA, Stack G. 2013. Limiting the extent of a delayed hemolytic transfusion reaction with automated red blood cell exchange. Arch Pathol Lab Med. 137(6):861-864.
An article with several authors:
(Superscript numeral): Zagarins SE, Ronnenberg AG, Gehlbach SH, Lin R, Bertone-Johnson ER. Are existing measures of overall diet quality associated with peak bone mass in young premenopausal women? J Hum Nutr Diet. 2012;25(2):172-179.
(Name-year):Zagarins SE, Ronnenberg AG, Gehlbach SH, Lin R, Bertone-Johnson ER. 2012. Are existing measures of overall diet quality associated with peak bone mass in young premenopausal women? J Hum Nutr Diet. 25(2):172-179.
For an article with more than ten authors, list the first ten authors and end that part of the citation with "et al."
If your source doesn't provide an abbreviated title for the journal, look the journal up in NLM Catalog to find out how it should be abbreviated.
For an article in a freely available online journal:
(Superscript numeral):Coetzer W, Hamer M, Parker-Allie F. A new era for specimen databases and biodiversity information management in South Africa. Biodiversity Informatics. 2012 [cited 2013 July 3];8:1-11.
(Name-year): Coetzer W, Hamer M, Parker-Allie F. 2012. A new era for specimen databases and biodiversity information management in South Africa. Biodiversity Informatics. [Cited 2013 July 3];8:1-11.
For book chapters (note: these examples all follow the superscript numeral in-text citation pattern. If you're using name-date in-text citations, just move the date to after the title):
If you're citing a chapter from a book that was written by a single author or authors, you need to cite the full book before you cite the chapter.
Author AA. Title of book. Place of publication (two-letter abbreviation for state or country - see this table for country codes): Publisher; Year. Chapter number, Title of chapter; p. #-#.
Hillstrom K. U.S. health policy and politics: a documentary history. Washington (DC): CQ Press; 2012. Chapter 3, The professionalization of American medicine, 1860-1890; p. 84-132.
If you're citing a chapter that was contributed to an edited book, cite the chapter and then the book itself:
Author AA. Title of chapter. In: Author BB. Title of book. Place of publication (two-letter abbreviation for state or country - see this table for country codes): Publisher; Year. p. #-#.
Pastel RH, Ritchie EC. Mitigation of psychological effects of weapons of mass destruction. In: Ritchie EL, Watson PJ, Friedman MJ, editors. Interventions following mass violence and disasters: strategies for mental health practice. New York (NY): Guilford Press; 2006. p. 300-318.