@article{SF_1984__29_134680,
     author = {K.D. jr. Magill},
     title = {Congruences on semigroups of continuous selfmaps.},
     journal = {Semigroup forum},
     pages = {159--182},
     year = {1984},
     volume = {29},
     zbl = {0551.20050},
     url = {http://geodesic.mathdoc.fr/item/SF_1984__29_134680/}
}