Karya, U., Rani, A., & Srivastava, A. (2021). Tocolytic effect of combined sildenafil citrate and nifedepine versus nifedipine alone for management of preterm labour at a tertiary centre. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, 10(4), 1596–1601. https://doi.org/10.18203/2320-1770.ijrcog20211143