@article{GDZPPN001265172, title = {Perfect monoids revisited.}, journal = {Semigroup forum}, volume = {53}, year = {1996}, pages = {225-229}, zbl = {0865.20053}, url = {http://dml.mathdoc.fr/item/GDZPPN001265172} }
Kilp, M. Perfect monoids revisited.. Semigroup forum, Tome 53 (1996) pp. 225-229. http://gdmltest.u-ga.fr/item/GDZPPN001265172/