Targan, Maria, Dariusz Świetlik, Aleksandra Kicińska, Karolina, and Tomasz. 2018. “Knowledge of University Students from the Metropolitan Area of Gdansk on Physiology of Procreative Health and Fertility Awareness-Based Methods)”. Quarterly Journal Fides Et Ratio 35 (3), 55-69. https://fidesetratio.com.pl/ojs/index.php/FetR/article/view/516.