Bączek, Grażyna, Beata Manista, and Urszula Tataj -Puzyna. 2017. “Knowledge and Opinions of Medical Staff on Natural Fertility Awareness Methods ”. Quarterly Journal Fides Et Ratio 32 (4): 215-32. https://fidesetratio.com.pl/ojs/index.php/FetR/article/view/628.