Mоrdоvets N. T., “Asymptotics of the sum of one class of Feinman graphs”, Ukr. Mat. Zhurn., vol. 18, no. 1, pp. 66–73, Jan. 1966, Accessed: Apr. 09, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/8653