Gaya APA

O'Brien, P, S. et al (2007). The Premenstrual Syndromes : PMS and PMDD . : Informa Healthcare USA, Inc..

Gaya MLA

O'Brien, PM, Shaughn. et al. "The Premenstrual Syndromes : PMS and PMDD". : Informa Healthcare USA, Inc., 2007. Text.