%0 Journal Article %A J. W. S. Cassels %T On sums of squares %J Trudy Matematicheskogo Instituta imeni V.A. Steklova %D 1973 %P 114-117 %V 132 %I mathdoc %U http://geodesic.mathdoc.fr/item/TM_1973_132_a14/ %G ru %F TM_1973_132_a14