%0 Journal Article %A G. A. Kalyabin %T A necessary and sufficient condition for the discreteness of the spectrum of a monomial operation in the matrix case %J Differencialʹnye uravneniâ %D 1973 %P 951-954 %V 9 %N 5 %I mathdoc %U http://geodesic.mathdoc.fr/item/DE_1973_9_5_a20/ %G ru %F DE_1973_9_5_a20