O. E. Bezushchak and V. I. Sushchanskii, “Groups of Periodically Defined Linear Transformations of an Infinite-Dimensional Vector Space”, Ukr. Mat. Zhurn., vol. 67, no. 10, pp. 1299–1308, Oct. 2015, Accessed: Dec. 05, 2025. [Online]. Available: https://umj.imath.kiev.ua/index.php/umj/article/view/2067