Arnold, David M. Finite rank torsion free abelian groups and rings / David M. Arnold. - Berlin : Springer, 1982. - 191 p. - Lecture notes in mathematics ; LNM ; v. 931 v. 931 . ISBN: 3-540-11557-9 0-387-11557-9 Descriptores--Materias: Group theory. Subjects--Index Terms: Teorķa de grupos.