Khomenko, N. P. and Strok, V. V. (1971) “Some combinatorial identities for sums of compositional coefficients ”, Ukrains’kyi Matematychnyi Zhurnal, 23(6), pp. 830-837. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/8636 (Accessed: 15February2025).