@article{AUCMP_1981_22_1_a6,
     author = {Kepka, Tom\'a\v{s}},
     title = {On a class of groupoids},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {29--49},
     year = {1981},
     volume = {22},
     number = {1},
     mrnumber = {0635975},
     zbl = {0481.08002},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_1981_22_1_a6/}
}