On intermediate symmetrically normed ideals

I. Ts. Gokhberg and M. G. Krein, Introduction to the Theory of Linear Nonselfadjoint Operators [in Russian], Nauka, Moscow (1965).

B. S. Mityagin, Matem. Sb.,66, No. 4, 473–482 (1965).

B. S. Mityagin, Izv. AN SSSR, Ser. Matem.,28, No. 4, 819–832 (1964).

Ky Fan, Proc. Nat. Acad. Sci. USA,37, 760–766 (1951).

A. S. Markus, UMN,19, No. 4 (118), 93–123 (1964).

I. Ts. Gokhberg and M. G. Krein, Theory of Volterra Operators in Hilbert Space and Its Applications [in Russian], Nauka, Moscow (1967).