RadzievskayaE. I., and RadzievskiiG. V. “On One Extremal Problem for a Seminorm on the Space $l_1$ With Weight”. Ukrains’kyi Matematychnyi Zhurnal 57, no. 7 (July 25, 2005): 1002–1006. Accessed November 22, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/3659.