Kartikasari, M., and L. Aktovianta. “Meta-Analysis: The Effect of Waterbirth Delivery Method on the Risk of Perineal Rupture”. Journal of Epidemiology and Public Health, vol. 6, no. 4, Oct. 2021, pp. 505-20, https://www.jepublichealth.com/index.php/jepublichealth/article/view/454.