admin. “Yo. V. Ostrovskii (April 6, 1934 - November 29, 2020) (in Ukrainian)”. Matematychni Studii 54, no. 2 (December 26, 2020): 222-224. Accessed April 25, 2024. http://matstud.org.ua/ojs/index.php/matstud/article/view/166.