%0 Journal Article
%A V. A. Lifshits
%T Deductive validity and reduction classes
%J Zapiski Nauchnykh Seminarov POMI
%D 1967
%P 69-77
%V 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/ZNSL_1967_4_a7/
%G ru
%F ZNSL_1967_4_a7