Raheja, A., Agarwal, K., Pachori, R. and Gandhi, G. (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), pp. 342–347. doi: 10.18203/2320-1770.ijrcog20196045.