%0 Journal Article
%A V. A. Yankov
%T Three sequences of formulas with two variables in the positive propositional logic
%J Izvestiya. Mathematics 
%D 1968
%P 845-848
%V 2
%N 4
%I mathdoc
%U http://geodesic.mathdoc.fr/item/IM2_1968_2_4_a9/
%G en
%F IM2_1968_2_4_a9