Ferreira, C. A., Álvaro N. Atallah, and C. A. de S. Loureiro. “Detecting the Extent of Control over Selection Bias Relating to Oral Health and Otorhinolaryngology: Cross-Sectional Study”. São Paulo Medical Journal, vol. 138, no. 3, June 2020, pp. 184-9, https://periodicosapm.emnuvens.com.br/spmj/article/view/634.