TY - JOUR AU - V. V. Arestov TI - Best approximation ol unbounded operators invariant with respect to a~shift by the linear bounded operators JO - Trudy Matematicheskogo Instituta imeni V.A. Steklova PY - 1992 SP - 3 EP - 20 VL - 198 PB - mathdoc UR - http://geodesic.mathdoc.fr/item/TM_1992_198_a0/ LA - ru ID - TM_1992_198_a0 ER -