Saeed, S., M. Saeed, A. Azhar, and A. Saeed. “Role of 17 Beta Estradiol in Etiology of Premenstrual Syndrome in Medical Students”. Annals of Punjab Medical College (APMC), Vol. 14, no. 2, June 2020, pp. 160-3, doi:10.29054/apmc/2020.744.