A. M. Samoilenko, “Life and work of N. N. Bogolyubov (on his 100th birthday)”, Ukr. Mat. Zhurn., vol. 61, no. 8, pp. 1130–1141, Aug. 2009, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3085