When writing in the APA format, you can use URLs in the references section of your article if the cited material does not have a permanent digital identifier given by the publisher. The URL you cite in the references section of your article should be the URL of the main page of the journal that published the article -- not the direct URL to the article. This will allow readers to locate the article if the exact URL changes or if the article is archived on the website you are citing.
Locate the names of all of the authors, the year of publication and the title for the article you are citing.
Locate the name, edition page numbers and URL of the journal you are citing.
Type your reference with the URL at the end. Make sure that every line after the first line is indented. The format should look like this:
First Author Last Name, First Author Initials, Second & Third Author Names. (Publication Year). Full Title of Article. [italicized] Journal of Article, [italicized] volume number, page numbers. Retrieved from http://www.TheJournalName.org
Here is an example:
Lodewijkx, H. F. M. (2001). Individual-group continuity in cooperation and competition under varying communication conditions. [italicized] Current Issues in Social Psychology, [italicized] 6(12), 166-182. Retrieved from
http://www.uiowa.edu/~grpproc/crisp/crisp.6.12.htm