Berezansky, Y. M., M. B. Vereikina, S. F. Kolyada, O. Y. Romanenko, A. G. Sivak, and V. V. Fedorenko. “Aleksandr Nikolaevich Sharkovsky (on His 60th Birthday)”. Ukrains’kyi Matematychnyi Zhurnal, Vol. 48, no. 12, Dec. 1996, pp. 1602-3, https://umj.imath.kiev.ua/index.php/umj/article/view/5183.