CHEPYZHOV, V. V.; VISHIK, M. I. Periodic processes and non-autonomous evolution equations with time-periodic terms. Topological Methods in Nonlinear Analysis, [S. l.], v. 4, n. 1, p. 1–17, 1994. Disponível em: https://apcz.umk.pl/TMNA/article/view/TMNA.1994.020. Acesso em: 18 apr. 2024.