Santos, Eliane Vieira dos, Rita de Cássia Maria dos Santos Frazão, and Sheyla Costa de Oliveira. “Feeling of Women Regarding the Use of the Billings Ovulation Method”. Rev Rene 18, no. 1 (June 12, 2017): 11–18. Accessed February 23, 2025. http://200.129.40.241/rene/article/view/18859.