The construction of asymptotic solutions of a singularly perturbed linear system of differential equations with an irregular singular point in the case where the main matrix has multiple spectrum. Neliniini Kolyvannya, [S. l.], v. 11, n. 1, p. 128–144, 2008. Disponível em: https://twinhead.imath.kiev.ua/index.php/nosc/article/view/467. Acesso em: 21 jan. 2026.