MINENKO, A. S. On minimization of one integral functional by the Ritz method. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 58, n. 10, p. 1385–1394, 2006. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3540. Acesso em: 5 dec. 2025.