Kim, Sung Guen. “Extreme and Exposed Symmetric Bilinear Forms on the Space ${\mathcal L}_{s}(^2 l_{\infty}^2)$”. Carpathian Mathematical Publications 12, no. 2 (December 13, 2020): 340–352. Accessed April 24, 2024. https://journals.pnu.edu.ua/index.php/cmp/article/view/4167.