@article{MZ_1978__164_172770,
     author = {Richard C. Vrem},
     title = {Lacunarity on {Compact} {Hypergroups.}},
     journal = {Mathematische Zeitschrift},
     pages = {93--104},
     publisher = {mathdoc},
     volume = {164},
     year = {1978},
     zbl = {0389.43005},
     url = {http://geodesic.mathdoc.fr/item/MZ_1978__164_172770/}
}