%0 Journal Article %A M. Ya. Azbel' %T On the spectrum of difference equations with periodic coefficients %J Doklady Akademii Nauk %D 1964 %P 703-706 %V 159 %N 4 %I mathdoc %U http://geodesic.mathdoc.fr/item/DAN_1964_159_4_a0/ %G ru %F DAN_1964_159_4_a0