A digital object identifier (DOI) is a unique alphanumeric string assigned by a registration agency (the International DOI Foundation) to identify content and provide a persistent link to its location on the Internet. The publisher assigns a DOI when the article is published and made available electronically. The DOI can be found in the citation for the article from the database you are searching or sometimes printed on the article near the copyright information. 

If no DOI has been assigned and you are accessing the periodical online, use the URL of the website from which you are retrieving the periodical. See the flowchart below for more information.

Author's Last Name, Author's First Initial. Author's Middle Initial. (Year, Month/Date/Season). 
          Title of article. Title of Journal/Magazine, Volume(Issue), Page(s). doi:xx.xxxxxxx

Sutherland, M. B. (2000). Problems of diversity in policy and practice: Celtic
          languages in the United Kingdom. Comparative Education, 36(2), 199-209.
          doi:10.1080/03050060050045363

Elmer-DeWitt, P., & Farley, C. J. (1994 June). People who eat Hostess
          Twinkies.  Time, 143(12), 22. 

Gubbins, H., O'Halloran, S., Kearney, D., Dore, A., Magner, E., & Murphy, E. (2007). A forum for the practice of musicology in Ireland. 

British Postgraduate Musicology, 9, 5.

Clay, R. (2008, June). Science vs. ideology: Psychologists fight back about the 
          misuse of research.  Monitor on Psychology, 39(6), Retrieved from 
          http://www.apa.org/monitor