Vasylyshyn, T.V. “Continuous Block-Symmetric Polynomials of Degree at Most Two on the Space $(L_\infty)^2$”. Carpathian Mathematical Publications 8, no. 1 (June 30, 2016): 38–43. Accessed November 22, 2024. https://vps.pnu.edu.ua/index.php/cmp/article/view/1412.