Same two authors publishing in the same year:
Adachi, P. J. C., & Willoughby, T. (2011a). The effect of video game competition and violence on aggressive behavior: Which characteristic has the greatest inﬂuence? Psychology of Violence, 1(4), 259–274. doi:10.1037/a0024908
The digital object identifier (doi) is a code that indicates the url location of the article in electronic format, under certain circumstances it can be used as a link to the item, assuming the access is open to the searcher.
Adachi, P. J. C., & Willoughby, T. (2011b). The effect of violent video games on aggression: Is it more than just the violence? Aggression and Violent Behavior, 16, 55–62. doi:10.1016/j.avb.2010.12.002
Notice the change in the dates, also the italicized journal title and volume. The (no.) is necessary when each issue starts with page 1.
When there are more than seven authors:
Anderson, C. A., Shibuya, A., Ihori, N., Swing, E. L., Bushman, B. J., Sakamoto, A.,... Saleem, M. (2010). Violent video game effects on aggression, empathy, and prosocial behavior in Eastern and Western countries: A meta-analytic review. Psychological Bulletin, 136, 151–173. doi:10.1037/a0018251
Watts, D. J. (2011). Everything is obvious, once you know the answer: How common sense fails us. New York, NY:Crown Business/Random House.
U.S. Department of Health and Human Services. (2001). Youth violence: A report of the Surgeon General. Retrieved from http://www.surgeongeneral.gov/library/youthviolence/report.html
Vossekuil, B., Fein, R., Reddy, M., Borum, R., & Modzeleski, W. (2002). The ﬁnal report and ﬁndings of the Safe School Initiative: Implications for the prevention of school attacks in the United States. Washington, DC: U. S. Department of Education and U. S. Secret Service. Retrieved from http://www.secretservice.gov/ntac/ssi_ﬁnal_report.pdf
Australian Government, Attorney-General’s Department. (2010). Literature review on the impact of playing violent video games on aggression. Barton, Australian Capital Territory, Australia: Commonwealth of Australia. Retrieved from http://www.apa.org/divisions/div46/articles.html
Bill and Melinda Gates Foundation. (2013). How we work: Grant opportunities. Retrieved from http://www.gatesfoundation.org/How-We-Work/General-Information/Grant-Opportunities
Gates, B. and Gates, M.. (n.d.) Who we are: Letter from Bill and Melinda Gates. Retrieved from Bill & Melinda Gates Foundation website: http://www.gatesfoundation.org/Who-We-Are/General-Information/Letter-from-Bill-and-Melinda-Gates
Full text items accessed through ERIC:
Gritter, J. L. (2009). Hospitious adoption: How hospitality empowers children and transforms adoption. Atlanta GA: Child Welfare League of America. Retrieved from http://www.eric.ed.gov/PDFS/ED504496.pdf
Omer, K. and Ali, D. (2011). The effect of culture integrated language courses on foreign language education. US-China Education Review, 8(3), 257-263. Retrieved from http://www.eric.ed.gov/PDFS/ED519574.pdf
For Additional and Alternative Examples:
See Sec. 7 (pp. 193-224) of the Publication Manual of the American Psychological Association, 6th ed. on reserve in Carlson Library.