BABENKO, V. F.; GLUSHKO, V. N. On the uniqueness of elements of the best approximation and the best one-sided approximation in the space $L_1$. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 46, n. 5, p. 475–483, 1994. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5711. Acesso em: 5 dec. 2025.