@article{SLC_1997_39_a5,
     author = {Helmut Kr\"amer},
     title = {Inversion of {Incidence} {Mappings}},
     journal = {S\'eminaire lotharingien de combinatoire},
     year = {1997},
     volume = {39},
     url = {http://geodesic.mathdoc.fr/item/SLC_1997_39_a5/}
}