Ismailov, V. E. “On the Uniqueness of Representation by Linear Superpositions”. Ukrains’kyi Matematychnyi Zhurnal 68, no. 12 (December 25, 2016): 1620–1628. Accessed April 11, 2025. https://umj.imath.kiev.ua/index.php/umj/article/view/1948.