Silvanovich, Olga V., and Nikolai A. Shirokov. 2020. “Approximation by Entire Functions on a Countable Union of Segments on the Real Axis. 3. Further Generalization”. Vestnik of Saint Petersburg University. Mathematics. Mechanics. Astronomy 5 (2):270-77. https://math-mech-astr-journal.spbu.ru/article/view/8521.