@article{IM_1968__5_141903,
     author = {J. TITS},
     title = {Formes quadratiques, groupes orthogonaux et algebres de {Clifford.}},
     journal = {Inventiones mathematicae},
     pages = {19--41},
     publisher = {mathdoc},
     volume = {5},
     year = {1968},
     zbl = {0155.05202},
     url = {http://geodesic.mathdoc.fr/item/IM_1968__5_141903/}
}