DAS, G. Some Inclusion Theorems for Norlund Methods. The Journal of the Indian Mathematical Society, [S. l.], v. 35, n. 1-4, p. 241–248, 1971. DOI: 10.18311/jims/1971/16734. Disponível em: http://informaticsjournals.com/index.php/jims/article/view/16734. Acesso em: 3 may. 2024.