@article{IM_1973__21_142222,
     author = {Richard Elman and T.Y. Lam},
     title = {Quadratic {Forms} and the {?-Invariant.} {II.}},
     journal = {Inventiones mathematicae},
     pages = {125--138},
     publisher = {mathdoc},
     volume = {21},
     year = {1973},
     zbl = {0267.10029},
     url = {http://geodesic.mathdoc.fr/item/IM_1973__21_142222/}
}