TY - JOUR AU - M. O. Otelbaev TI - Estimates of $s$-numbers and completeness conditions for systems of root vectors of non-self-adjoint Sturm--Liouville operators JO - Matematičeskie zametki PY - 1979 SP - 409 EP - 418 VL - 25 IS - 3 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/MZM_1979_25_3_a8/ LA - ru ID - MZM_1979_25_3_a8 ER -