APA (7th ed.) Citation

Zelnik, Kantner, & Ford. (1981). Sex and pregnancy in adolescence. Sage Publications.

Chicago Style (17th ed.) Citation

Zelnik, Kantner, and Ford. Sex and Pregnancy in Adolescence. London: Sage Publications, 1981.

MLA (8th ed.) Citation

Zelnik, et al. Sex and Pregnancy in Adolescence. Sage Publications, 1981.