@article{AM2_1980__21_182409,
     author = {T.M.K. Davison},
     title = {A functional equation for quadratic forms.},
     journal = {Aequationes mathematicae},
     pages = {1--7},
     publisher = {mathdoc},
     volume = {21},
     year = {1980},
     zbl = {0451.39008},
     url = {http://geodesic.mathdoc.fr/item/AM2_1980__21_182409/}
}