%0 Journal Article %A V. M. Ryabtseva %T Values of the characteristic function of an isometric operator on the boundary, and the spectrum of its bounded orthogonal extension %J Izvestiâ vysših učebnyh zavedenij. Matematika %D 1969 %P 74-78 %N 7 %I mathdoc %U http://geodesic.mathdoc.fr/item/IVM_1969_7_a10/ %G ru %F IVM_1969_7_a10