@article{IM_1992__110_2_144047,
     author = {N\'andor Sim\'anyi},
     title = {The {K-property} of {N} billiard balls {II.} {Computation} of neutral linear spaces.},
     journal = {Inventiones mathematicae},
     pages = {151--172},
     publisher = {mathdoc},
     volume = {110},
     number = {2},
     year = {1992},
     zbl = {0767.58030},
     url = {http://geodesic.mathdoc.fr/item/IM_1992__110_2_144047/}
}