@article{2447, author = {Henney, Dagmar R.}, title = {N-parameter semigroups}, journal = {Portugaliae mathematica}, volume = {24}, year = {1965}, pages = {31-37}, zbl = {0139.06803}, mrnumber = {0195981}, language = {en}, url = {http://dml.mathdoc.fr/item/2447} }
Henney, Dagmar R. N-parameter semigroups. Portugaliae mathematica, Tome 24 (1965) pp. 31-37. http://gdmltest.u-ga.fr/item/2447/