YAKOVETS , V. P. Construction of asymptotic solutions of linear singularly disturbed second-order system with degenerations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 44, n. 8, p. 1102–1112, 1992. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/8040. Acesso em: 5 dec. 2025.