@article{10_4153_CJM_1977_118_7,
     author = {Petrich, Mario},
     title = {Certain {Varieties} and {Quasivarieties} of {Completely} {Regular} {Semigroups}},
     journal = {Canadian journal of mathematics},
     pages = {1171--1197},
     year = {1977},
     volume = {29},
     number = {6},
     doi = {10.4153/CJM-1977-118-7},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1977-118-7/}
}