@article{10_4153_CJM_1989_020_6,
     author = {Petrich, Mario},
     title = {Congruences on {Completely} {Regular} {Semigroups}},
     journal = {Canadian journal of mathematics},
     pages = {439--461},
     year = {1989},
     volume = {41},
     number = {3},
     doi = {10.4153/CJM-1989-020-6},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1989-020-6/}
}