@article{GDZPPN001257218, title = {Semigroups for which the continuum congruences form finite chains.}, journal = {Semigroup forum}, volume = {30}, year = {1984}, pages = {221-230}, zbl = {0533.20037}, url = {http://dml.mathdoc.fr/item/GDZPPN001257218} }
Magill, K.D. jr. Semigroups for which the continuum congruences form finite chains.. Semigroup forum, Tome 30 (1984) pp. 221-230. http://gdmltest.u-ga.fr/item/GDZPPN001257218/