@article{GDZPPN001253565,
title = {The structure of an idempotent relation.},
journal = {Semigroup forum},
volume = {18},
year = {1979},
pages = {319-330},
zbl = {0424.04001},
url = {http://dml.mathdoc.fr/item/GDZPPN001253565}
}
Norris, E.M. The structure of an idempotent relation.. Semigroup forum, Tome 18 (1979) pp. 319-330. http://gdmltest.u-ga.fr/item/GDZPPN001253565/