BABENKO, V. F.; RUDENKO, A. A. On the optimal renewal of bilinear functionals in linear Normed spaces. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 6, p. 828–831, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5067. Acesso em: 5 dec. 2025.