Devasia, N., and T. Philip. “A Study of Factors Affecting Regression of βhCG in Gestational Trophoblastic Disorders”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, vol. 8, no. 3, Feb. 2019, pp. 955-60, doi:10.18203/2320-1770.ijrcog20190864.