CHAIKOVS'KYI, A. V. Functions of shift operator and their applications to difference equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 62, n. 10, p. 1408–1419, 2010. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/2965. Acesso em: 5 dec. 2025.