Naddoni, D. B., Balakundi, S. K., & Assainar, K. K. (2017). The effect of nitrous oxide (entonox) on labour. International Journal of Reproduction, Contraception, Obstetrics and Gynecology, 5(3), 835–839. https://doi.org/10.18203/2320-1770.ijrcog20160594