@article{MOMA_1980__89_177949,
     author = {Klaus Hartmann},
     title = {[FIA]... {Gruppen} und {Hypergruppen.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {9--18},
     publisher = {mathdoc},
     volume = {89},
     year = {1980},
     zbl = {0415.43009},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1980__89_177949/}
}