Nitrous oxide for relief of labor pain: A systematic review. American Journal of Obstetrics and Gynecology. May 2002, 186 (5 Suppl): 110–126. PMID 12011877. doi:10.1016/S0002-9378(02)70186-5.
Nitrous oxide for relief of labor pain: A systematic review. American Journal of Obstetrics and Gynecology. May 2002, 186 (5 Suppl): 110–126. PMID 12011877. doi:10.1016/S0002-9378(02)70186-5.