@article{IM_1976__36_142422,
     author = {J. Tits},
     title = {Non-existence de certains polygones g\'en\'eralis\'es, {I.}},
     journal = {Inventiones mathematicae},
     pages = {275--284},
     publisher = {mathdoc},
     volume = {36},
     year = {1976},
     zbl = {0369.20004},
     url = {http://geodesic.mathdoc.fr/item/IM_1976__36_142422/}
}