@article{GDZPPN00203753X, title = {Subadditive functions on modules and subgroups of abelian groups.}, journal = {Aequationes mathematicae}, volume = {38}, year = {1989}, pages = {15-37}, zbl = {0668.39004}, url = {http://dml.mathdoc.fr/item/GDZPPN00203753X} }
Pelling, M.J. Subadditive functions on modules and subgroups of abelian groups.. Aequationes mathematicae, Tome 38 (1989) pp. 15-37. http://gdmltest.u-ga.fr/item/GDZPPN00203753X/