%0 Journal Article %A V. N. Lugovoi %T Propagation of wave beams in non-linear media %J Doklady Akademii Nauk %D 1967 %P 58-61 %V 176 %N 1 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1967_176_1_a14/ %G ru %F DAN_1967_176_1_a14