@article{GDZPPN001251759,
title = {Right PP monoids with central idempotents.},
journal = {Semigroup forum},
volume = {12},
year = {1976},
pages = {229-238},
zbl = {0353.20051},
url = {http://dml.mathdoc.fr/item/GDZPPN001251759}
}
Fountain, J. Right PP monoids with central idempotents.. Semigroup forum, Tome 12 (1976) pp. 229-238. http://gdmltest.u-ga.fr/item/GDZPPN001251759/