Hassan, W., M. Abu-Helalah, A. Salam, A. Elhakim, H. Bayazeed, S. Latif, and R. Rehmani. “Incidence of Early Pregnancy Bleeding in the Eastern Region of Saudi Arabia”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol. 5, no. 5, Jan. 2017, pp. 1392-9, doi:10.18203/2320-1770.ijrcog20161292.