@article{AUCMP_1997_38_1_a4,
     author = {Dr\'apal, A. and Je\v{z}ek, J. and Kepka, T.},
     title = {Groupoids and the associative law {IX.} {(Associative} triples in some classes of groupoids)},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {39--52},
     year = {1997},
     volume = {38},
     number = {1},
     mrnumber = {1489851},
     zbl = {0889.20042},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_1997_38_1_a4/}
}