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2. Yu. I. Lyubich, Introduction to the Theory of Banach Representations of Groups, Birkhäuser, Basel etc. (1988).
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4. Yu. I. Lyubich, V. I. Matsaev, and G. M. Feldman, “On representations with a separable spectrum” [in Russian], Funkts. Anal. Prilozh. 7, No. 2, 52–61 (1973); English transl.: Funct. Anal. Appl. 7, No. 2, 129–136 (1973).
5. A. G. Baskakov, “Representation theory for Banach algebras, Abelian groups, and semigroups in the spectral analysis of linear operators” [in Russian], Sovrem. Mat., Fundam. Napravl. 9, 3–151 (2004); English transl.: J. Math. Sci. 137, No. 4, 4885–5036 (2006).