Factorizations of the characteristic function and invariant subspaces of a nonexpanding operator
Tài liệu tham khảo
B. S. Nagy and C. Foias, Harmonic Analysis of Operators on Hilbert Space, American Elsevier (1971).
V. M. Brodskii, "On operator nodes and their characteristic functions," Dokl. Akad. Nauk SSSR,198, No. 1, 16–19 (1971).
M. S. Brodskii, Triangular and Jordan Representations of Linear Operators [in Russian], Nauka, Moscow (1969).