TY - JOUR AU - I. V. Mel'nikova TI - The family $M$, $N$ of operator functions and second-order equations in Banach space JO - Izvestiâ vysših učebnyh zavedenij. Matematika PY - 1985 SP - 45 EP - 52 IS - 2 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/IVM_1985_2_a5/ LA - ru ID - IVM_1985_2_a5 ER -