Raczkiewicz, P., N. Śmiech, T. Korzec, K. Kania, and M. Kaczerska. “COVID-19 and Threats to Pregnancy and the Fetus”. Journal of Education, Health and Sport, vol. 11, no. 4, Apr. 2021, pp. 11-17, doi:10.12775/JEHS.2021.11.04.001.