Piekarska, E., Pawlicki, M., Łopuszyńska, A., Kozioł, M., Krasa, A. and Piecewicz-Szczęsna, H. (2021) “Association Between Male fertility and Vitamin D”, Journal of Education, Health and Sport, 11(8), pp. 322–327. doi: 10.12775/JEHS.2021.11.08.035.