CHOUDHARY, A.; MAHESHWARI, S.; PALIWAL, N.; UJWAL, S.; SINGARIYA, G. Comparative study of fentanyl versus tramadol as adjuvant with low dose local anaesthetic ropivacaine (0.1%) for epidural labour analgesia. International Journal of Research in Medical Sciences, [S. l.], v. 8, n. 9, p. 3309–3314, 2020. DOI: 10.18203/2320-6012.ijrms20203684. Disponível em: Acesso em: 28 mar. 2023.