%0 Journal Article %A V. P. Orevkov %T Undecidable classes of formulas for the constructive predicate calculus.~I %J Informatics and Automation %D 1972 %P 100-108 %V 121 %I mathdoc %U http://geodesic.mathdoc.fr/item/TRSPY_1972_121_a5/ %G ru %F TRSPY_1972_121_a5