ERMOLAEVA, P. G.; CHEREPENNIKOV, V. B. Polynomial quasisolutions of linear second-order differential-difference equations. Ukrains’kyi Matematychnyi Zhurnal, [S. l.], v. 60, n. 1, p. 140–152, 2008. Disponível em: https://umj.imath.kiev.ua/index.php/umj/article/view/3144. Acesso em: 7 apr. 2025.