Perturbation Theory for Linear Operators (Classics in Mathematics, 132): Kato, Tosio: 9783540586616: Amazon.com: Books
,Linear Operators in Hilbert Spaces | SpringerLink,Amazon.com: Theory of Linear Operators in Hilbert Space (Dover Books on Mathematics): 9780486677484: Akhiezer, N. I., Glazman, I. M.: Books,Perturbation Theory for Linear Operators (Classics in Mathematics, 132): Kato, Tosio: 9783540586616: Amazon.com: Books,Perturbation Theory for Linear Operators (Classics in Mathematics, 132): Kato, Tosio: 9783540586616: Amazon.com: Books