@article{GDZPPN00125488X, title = {Group ideals in a semigroup of measures.}, journal = {Semigroup forum}, volume = {23}, year = {1981}, pages = {325-330}, zbl = {0472.28005}, url = {http://dml.mathdoc.fr/item/GDZPPN00125488X} }
Shum, Kar-Ping. Group ideals in a semigroup of measures.. Semigroup forum, Tome 23 (1981) pp. 325-330. http://gdmltest.u-ga.fr/item/GDZPPN00125488X/