LAMBA, A.; SARDANA, P.; KAUR, R. Comparison of parenteral tramadol and epidural ropivacaine for labour analgesia: a prospective clinical study. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, [S. l.], v. 5, n. 6, p. 1722–1727, 2017. DOI: 10.18203/2320-1770.ijrcog20161479. Disponível em: https://www.ijrcog.org/index.php/ijrcog/article/view/1185. Acesso em: 4 dec. 2025.