HryshchenkoO. Y., KlyushinD. A., LyashkoS. I. and SergienkoI. V. (2012) “Ivan Ivanovych Lyashko (on his 90 th birthday)”, Ukrains’kyi Matematychnyi Zhurnal, 64(11), pp. 1568 - 1571. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/2681 (Accessed: 27July2024).