APA reference list example: Article in an online reference work. The author is listed by last name and initials: Swain, C. M. The year is listed in parentheses, followed by a period: (2004). The article title is Sociology of affirmative action. The word “In” is followed by the editors listed by initials and last names. The names are separated by an ampersand and the last name is followed by the abbreviation E d s period in parentheses: N. J. Smelser & P. B. Baltes (E d s period), The title of the reference work is italicized: International encyclopedia of the social and behavioral sciences. The words “Retrieved from” are followed by the URL, with no period at the end: http://www.sciencedirect.com/science/referenceworks/9780080430768