ŁOPATA, A. Drgania Samowzbudne Szczotki w Układzie Szczotka-Komutator. Engineering Transactions, [S. l.], v. 23, n. 1, p. 133–142, 1975. Disponível em: http://et.ippt.gov.pl/index.php/et/article/view/2345. Acesso em: 17 jan. 2026.