%0 Journal Article %A M. A. Naimark %T Investigation of the spectrum and the expansion in eigenfunctions of a nonselfadjoint operator of the second order on a semi-axis %J Trudy Moskovskogo matematičeskogo obŝestva %D 1954 %P 181-270 %V 3 %I mathdoc %U http://geodesic.mathdoc.fr/item/MMO_1954_3_a3/ %G ru %F MMO_1954_3_a3