%0 Journal Article
%A Colliot-Thélène, J.-L.
%T The Noether-Lefschetz theorem and sums of 4 squares in the rational function field $R(x, y)$
%J Compositio Mathematica
%D 1993
%P 235-243
%V 86
%N 2
%I Kluwer Academic Publishers
%U http://www.numdam.org/item/CM_1993__86_2_235_0/
%G en
%F CM_1993__86_2_235_0