KozubovskayaI. G. (1971) “On defence of theses at Academic Council of the Institute of Mathematics of the Academy of Sciences of the Ukrainian SSR in 1970—1971 ”, Ukrains’kyi Matematychnyi Zhurnal, 23(4), pp. 564-568. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/8594 (Accessed: 1September2024).