SJÖDIN, Gunnar. On Filtered Modules and their Associated Graded Modules. MATHEMATICA SCANDINAVICA, [S. l.], v. 33, p. 229–249, 1973. DOI: 10.7146/math.scand.a-11486. Disponível em: https://tidsskrift.dk/math/article/view/11486. Acesso em: 14 aug. 2026.