TY - JOUR AU - G. V. Radzievskii TI - Multiple completeness of root vectors of a Keldysh pencil perturbed by an operator-valued function analytic in a disc JO - Sbornik. Mathematics PY - 1973 SP - 323 EP - 347 VL - 20 IS - 3 UR - http://geodesic.mathdoc.fr/item/SM_1973_20_3_a1/ LA - en ID - SM_1973_20_3_a1 ER -