Baranovskyi, O. M., M. V. Pratsiovytyi, and H. M. Torbin. “Topological and Metric Properties of Sets of Real Numbers With Conditions on Their Expansions in Ostrogradskii Series”. Ukrains’kyi Matematychnyi Zhurnal 59, no. 9 (September 25, 2007): 1155–1168. Accessed April 18, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3379.