VINAYA, G.; SUREKHA, S. M.; CHINIWAL, S. Comparison of analgesic efficacy of intramuscular tramadol and pethidine in labour. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, [S. l.], v. 9, n. 10, p. 4197–4201, 2020. DOI: 10.18203/2320-1770.ijrcog20204313. Disponível em: https://www.ijrcog.org/index.php/ijrcog/article/view/8966. Acesso em: 25 nov. 2025.