1. Analytic functions of several Banach algebra elements;Arens, Richard;Ann. of Math. (2),1955
2. Séminaire de Géométrie Analytique (Paris, 1974/75), Asterisque, No. 36-37, Soc. Math. France. Paris, 1976.
3. N. Bourbaki, Théories spectrales, Hermann, Paris, 1967.
4. Functional calculus with sections of an analytic space;Putinar, Mihai;J. Operator Theory,1980