@article{JRAM_1932__167_149786,
     author = {L.J. Mordell},
     title = {On binary quadratic forms expressable as a sum of three linear squares with integer coefficients.},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {12--19},
     publisher = {mathdoc},
     volume = {167},
     year = {1932},
     zbl = {0003.19302},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1932__167_149786/}
}