Pichugov, S.A. (1996) “On the existence of a measurable function with given values of the best approximations in $L_0$”, Ukrains’kyi Matematychnyi Zhurnal, 48(8), pp. 1080–1085. Available at: https://umj.imath.kiev.ua/index.php/umj/article/view/5251 (Accessed: 26 April 2025).