@article{CMUC_1967_8_4_a0,
     author = {Havel, V\'aclav},
     title = {Ternary halfgroupoids and coordinatization {(Preliminary} communication)},
     journal = {Commentationes Mathematicae Universitatis Carolinae},
     pages = {569--580},
     year = {1967},
     volume = {8},
     number = {4},
     mrnumber = {0228404},
     zbl = {0192.26401},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/CMUC_1967_8_4_a0/}
}