Cite major encyclopedias and dictionaries with an in text note rather than a reference unless citing an article. Treat as if it is book chapter:
Electronic
Fagan, J. 2015. "Gangs And Drugs." Pp 565-74 in Encyclopedia of Drugs, Alcohol & Addictive Behavior, edited by R. Carson-DeWitt. New York: Macmillan Reference USA. Retrieved from http://go.galegroup.com/ps/i.do?id=GALE%7CCX3403100222&v=2.1&u=csus_main&it=r&p=GVRL&sw=w&asid=981e440c308e4d318bc77a1d9459bb73
Paper
C. Ridgeway. 2000. "Complex Organizations." Pp 392-400 in Encyclopedia of Sociology, Vol. 1, edited by E.F. Bargatta and R.V. Montgomery. New York: Macmillan Reference USA.