Pisaruk, A., N. Koshel, L. Pisaruk, and V. Shatilo. “Impact of COVID-19 on the Signs of Human Ageing”. Ageing and Longevity, Vol. 2, no. 2, July 2021, pp. 18-23, http://aging-longevity.org.ua/index.php/journal-description/article/view/31.