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2. Collins M. Top ten misconceptions about the use of nitrous oxide in labor. AWHONN Connections August 14, 2015. Available at: https://awhonnconnections.org/2015/08/14/top-ten-misconceptions-about-the-use-of-nitrous-oxide-in-labor/. Accessed May 15, 2016.
3. The use of Entonox® for labour pain should be abandoned. Proposer;Yentis;Int J Obstet Anesth,2001
4. The use of Entonox® for labour pain should be abandoned;Clyburn;Int J Obstet Anesth,2001
5. A history of nitrous oxide;Frost,1985