Dmytryshyn, M. I. “Tensor Products of Approximation Spaces Associated With Regular Elliptic Operators on Compact Manifolds”. Matematychni Studii 64, no. 2 (December 21, 2025): 170-178. Accessed January 8, 2026. http://matstud.org.ua/ojs/index.php/matstud/article/view/686.