O. V. Kotova, “Continuum cardinality of the set of solutions of one class of equations that contain the function of frequency of ternary digits of a number”, Ukr. Mat. Zhurn., vol. 60, no. 10, pp. 1414–1421, Oct. 2008, Accessed: Apr. 13, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/3255