%0 Journal Article
%A N. A. Potapkov
%T Perturbation theory with variational parameter. Inequalities and estimates for the free energy
%J Teoretičeskaâ i matematičeskaâ fizika
%D 1973
%P 407-416
%V 15
%N 3
%I mathdoc
%U http://geodesic.mathdoc.fr/item/TMF_1973_15_3_a12/
%G ru
%F TMF_1973_15_3_a12