Nelson Dunford, Jacob T. Schwartz, Linear Operators, Part I General Theory ISBN0-471-60848-3, Part II Spectral Theory, Self Adjoint Operators in Hilbert Space ISBN0-471-60847-5, Part III Spectral Operators ISBN0-471-60846-7
References
Obituary in Notices Amer. Math. Soc., Vol. 34, 1987, p.287