YAKOVETS , V. P. Asymptotic analysis of a singularly perturbed linear system with a singular limiting beam of matrices. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 44, n. 1, p. 106–122, 1992. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/7801. Acesso em: 6 dec. 2025.