Raheja, Aastha, Krishna Agarwal, Rini Pachori, and Gauri Gandhi. 2019. “Tramadol Versus Placebo for Labor Analgesia in Low Risk Women: A Randomized Controlled Trial”. International Journal of Reproduction, Contraception, Obstetrics and Gynecology 9 (1):342-47. https://doi.org/10.18203/2320-1770.ijrcog20196045.