SHUMEIKO, A. A. On lower bounds for the approximation of functions by local splines with nonfixed nodes. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 52, n. 1, p. 134–144, 2000. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/4403. Acesso em: 5 dec. 2025.