GEFTER, S.; PIVEN, A. Implicit linear difference equation in Frechet spaces . Reports of the National Academy of Sciences of Ukraine, Kyiv, Ukraine, n. 6, p. 3–8, 2024. DOI: 10.15407/dopovidi2017.06.003. Disponível em: https://nasu-periodicals.org.ua/index.php/dp/article/view/7521. Acesso em: 1 oct. 2024.