For article titles, only capitalize the first word and proper nouns and abbreviations that are ordinarily capitalized.
Use abbreviations of journal titles (use the PubMed Journals Database to get journal abbreviations).
References are numbered consecutively in the order they appear in the text. All references are at the end of the paper under the heading Reference List.
Include DOIs for online articles.
In-text citations are only used when a reference would not be included in a reference list, such as news articles, obituaries, and material submitted for publication but not yet accepted.
For in-text citations to articles:
If you have an article citation without a DOI, you can look up the DOI at CrossRef.org.
Likewise, if you have a DOI but not the citation information, you can look up the citation at DOI.org.
Some articles and journals do not provide DOIs--it is the publisher's preference to include or not to include a DOI. When citing an article without a DOI, check the style manual (AMA, APA, etc.) for guidance.
Include the DOI if available. If the DOI is not available, provide the URL, published date, and date accessed.
DOI Available:
Rowney R, Barton G. The role of public health nursing in emergency preparedness and response. Nurs Clin North Am. 2005;40(3):499-509. 
doi:10.1016/j.cnur.2005.04.005.
DOI not Available:
Rowney R, Barton G. The role of public health nursing in emergency preparedness and response. Nurs Clin North Am. 2005;40(3):499-509. http://www.sciencedirect.com/science/article/pii/S0029646505000216. Accessed November 9, 2013.
For 2-6 authors, list all authors. If there are 7 or more authors, list the first 3 followed by "et al."
1 Author:
Cropley TG. Dermatology and skin disease in the American Civil War. Dermatol Nurs. 2008;20(1):29-33.
More than 1 Author:
Rowney R, Barton G. The role of public health nursing in emergency preparedness and response. Nurs Clin North Am. 2005;40(3):499-509.
Seal AJ, Creeke PI, Dibari F, et al. Low and deficient niacin status and pellagra are epidemic in postwar Angola. Am J Clin Nutr. 2007;85(1):218-224.
For 2-6 authors, list all authors. If there are 7 or more authors, list the first 3 followed by "et al."
1 Author/Editor:
Bollet AJ. Civil War Medicine: Challenges and Triumphs. Tucson, AZ: Galen Press; 2002.
Frumkin H, ed. Environmental Health: From Global to Local. San Francisco, CA: Jossey-Bass; 2005.
More than 1 Author/Editor:
Kaplan C, Turner GS, Warrell DA. Rabies: The Facts. New York: Oxford University Press; 1986.
Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Philadelphia, PA: Mosby/Elsevier; 2010.
E-mail and personal communications are not listed in the Reference List. They should be included as in-text citations and should include the name and highest academic degree(s) of the sender.
Email:
(John Doe, Ph.D., e-mail communication, April 18, 2010)
Website:
Centers for Disease Control and Prevention Website. http://www.cdc.gov. Accessed April 13, 2010.
Web Page:
Major earthquake in Port-Au-Prince, Haiti avoid nonessential travel to Haiti. Centers for Disease Control and Prevention Website. http://wwwnc.cdc.gov/travel/content/travel-health-warning/haiti-earthquake.aspx. Published January 13, 2010. Updated July 21, 2010. Accessed October 12, 2010.