Oliveira, L. S., L. G. O. Brito, S. M. Quintana, G. Duarte, and A. C. Marcolin. “Perineal Trauma After Vaginal Delivery in Healthy Pregnant Women”. São Paulo Medical Journal, vol. 132, no. 4, Aug. 2014, pp. 231-8, https://periodicosapm.emnuvens.com.br/spmj/article/view/1227.