@article{GDZPPN002292084, title = {On the Uniqueness of Character Semigroups.}, journal = {Mathematische Annalen}, volume = {152}, year = {1963}, pages = {346-354}, zbl = {0114.25302}, url = {http://dml.mathdoc.fr/item/GDZPPN002292084} }
ROTHMAN, N.J. On the Uniqueness of Character Semigroups.. Mathematische Annalen, Tome 152 (1963) pp. 346-354. http://gdmltest.u-ga.fr/item/GDZPPN002292084/