AVDJAN, A. Limitation of solutions of some simultaneous differential equations with a retarded argument. Lithuanian Mathematical Journal, [S. l.], v. 6, n. 4, p. 465–473, 1966. DOI: 10.15388/LMJ.1966.19745. Disponível em: https://www.zurnalai.vu.lt/LMJ/article/view/19745. Acesso em: 22 aug. 2025.