KOVTUN, I. I. Fluctuations of forced vibrations in a medium with resistance. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 45, n. 1, p. 132–135, 1993. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/5792. Acesso em: 5 dec. 2025.