Minkin, Mary Jane; Wright, Carol V. (2003). "Morning-after contraception". The Yale guide to women's reproductive health: from menarche to menopause. New Haven: Yale University Press. p. 116. ISBN0-300-09820-0.
handle.net
hdl.handle.net
van Wagenen, Gertrude (December 1912). "Beta Zeta, Iowa State University". The Key. 29 (4). Columbus, Ohio: Kappa Kappa Gamma: 456. hdl:2027/mdp.39015075963077.