@article{CMUC_1982__23_1_a17,
     author = {Je\v{z}ek, Jaroslav},
     title = {The number of minimal varieties of idempotent groupoids},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {199--205},
     publisher = {mathdoc},
     volume = {23},
     number = {1},
     year = {1982},
     mrnumber = {653364},
     zbl = {0502.08008},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1982__23_1_a17/}
}