%0 Journal Article %A S. I. Pokhozhaev %T The Existence and Nonexistence of Periodic Solutions to Certain Nonlinear Hyperbolic Equations %J Informatics and Automation %D 1999 %P 260-285 %V 227 %I mathdoc %U http://geodesic.mathdoc.fr/item/TRSPY_1999_227_a18/ %G ru %F TRSPY_1999_227_a18