LuchkaA. Y. (1988). On the defences theses for a Doctor’s degree at the specialized council at the institute of mathematics of the Ukr.SSR Academy of sciences in 1987—1988 . Ukrains’kyi Matematychnyi Zhurnal, 40(5), 671-675. Retrieved from https://umj.imath.kiev.ua/index.php/umj/article/view/8827