%0 Journal Article
%A A. B. Venkov
%T Selberg's trace formula for the Hecke operator generated by an involution, and the eigenvalues of the Laplace--Beltrami operator on the fundamental domain of the modular group~$PSL(2,\mathbf Z)$
%J Izvestiya. Mathematics 
%D 1978
%P 448-462
%V 12
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IM2_1978_12_3_a1/
%G en
%F IM2_1978_12_3_a1