AZIZOV, M. On one direct method for the approximate solution of a periodic boundary-value problem. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 49, n. 9, p. 1157–1161, 1997. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5112. Acesso em: 5 dec. 2025.