Durna, N. “Partition of the Spectra for the Lower Triangular Double Band Matrix As Generalized Difference Operator Δv over the Sequence Spaces C and Lp (1 < P < ∞)”. Proyecciones (Antofagasta, On Line), vol. 39, no. 1, Feb. 2020, pp. 51-71, doi:10.22199/issn.0717-6279-2020-01-0004.