Mॱller, Vladimir. Spectral Theory of Linear Operators [electronic resource] and Spectral Systems in Banach Algebras by Vladimir Mॱller - Basel Birkh user Verlag AG 2007 http://dx.doi.org/10.1007/978-3-7643-8265-0 ISBN: 9783764382650 Dewey Class. No.: 515.722 / (e-book)