@article{GDZPPN001248480, title = {Building semigroups from groups (and reduced semigroups).}, journal = {Semigroup forum}, volume = {4}, year = {1972}, pages = {327-334}, zbl = {0273.20044}, url = {http://dml.mathdoc.fr/item/GDZPPN001248480} }
Grillet, P. Building semigroups from groups (and reduced semigroups).. Semigroup forum, Tome 4 (1972) pp. 327-334. http://gdmltest.u-ga.fr/item/GDZPPN001248480/