@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/