@article{AUCMP_1981__22_1_a2,
     author = {Vougiouklis, T.},
     title = {The set of hypergroups with operators which are constructed from a set with two elements},
     journal = {Acta Universitatis Carolinae. Mathematica et Physica},
     pages = {7--10},
     publisher = {mathdoc},
     volume = {22},
     number = {1},
     year = {1981},
     mrnumber = {0635971},
     zbl = {0493.20052},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AUCMP_1981__22_1_a2/}
}