@article{SF_1982__25_134570,
     author = {M. Petrich},
     title = {On the varieties of completely regular semigroups.},
     journal = {Semigroup forum},
     pages = {153--170},
     publisher = {mathdoc},
     volume = {25},
     year = {1982},
     zbl = {0502.20034},
     url = {http://geodesic.mathdoc.fr/item/SF_1982__25_134570/}
}