LuchkaA. Yu. 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), 671-75. https://umj.imath.kiev.ua/index.php/umj/article/view/8827.