Litvin, E. G., and O. V. Polyakov. “Asymmetric Approximations in the Space $L_{p(t)}$”. Ukrains’kyi Matematychnyi Zhurnal 51, no. 7 (July 25, 1999): 952-959. Accessed May 15, 2024. https://umj.imath.kiev.ua/index.php/umj/article/view/4684.