@article{SF_1976__12_134185,
     author = {A.H. Clifford},
     title = {The fundamental representation of a completely regular semigroup.},
     journal = {Semigroup forum},
     pages = {341--346},
     year = {1976},
     volume = {12},
     zbl = {0345.20060},
     url = {http://geodesic.mathdoc.fr/item/SF_1976__12_134185/}
}