Format: 

Author, A. A., Author, B. B., & Author, C. C. (Year, Month). Title of article. Title of Periodical, Volume(Issue), Pages. http://dx.doi.org/xxxxx or Retrieved from URL

Author, A. A., Author, B. B., & Author, C. C. (Year, Month). Title of article. Title of Periodical, Volume(Issue), Pages.

Examples: 

Rochester Regional Health. (2014, Winter). Rochester General to provide sports medicine support to RIT. Physician Connection Newsletter. Retrieved from http://www.rochestergeneral.org/healthcare-professionals/physican-connec...

In-text: (Rochester Regional Health, 2014)

Notes: 

Periodicals include items published on a regular basis such as journals, magazines, newspapers, and newsletters.

Source:
APA (ER) - no. 8