@article{SF_1985__32_134771,
     author = {L. Pol\'ak},
     title = {On varieties of completely regular semigroups.},
     journal = {Semigroup forum},
     pages = {97--123},
     publisher = {mathdoc},
     volume = {32},
     year = {1985},
     zbl = {0564.20034},
     url = {http://geodesic.mathdoc.fr/item/SF_1985__32_134771/}
}