@article{GDZPPN002051621, title = {Ueber symmetrische Monoide und Kegel.}, journal = {Commentarii mathematici Helvetici}, volume = {7}, year = {1934}, pages = {133-143}, zbl = {0007.32305}, url = {http://dml.mathdoc.fr/item/GDZPPN002051621} }
Emch, Arnold. Ueber symmetrische Monoide und Kegel.. Commentarii mathematici Helvetici, Tome 7 (1934) pp. 133-143. http://gdmltest.u-ga.fr/item/GDZPPN002051621/