@article{IM_1976__37_142431,
     author = {William C. Waterhouse},
     title = {Pairs of {Quadratic} {Forms.}},
     journal = {Inventiones mathematicae},
     pages = {157--164},
     year = {1976},
     volume = {37},
     zbl = {0337.10015},
     url = {http://geodesic.mathdoc.fr/item/IM_1976__37_142431/}
}