1. Structure of Algebras;Albert,1939
2. Structure theorems for a special class of Banach algebras;Ambrose;Trans. Amer. Math. Soc.,1945
3. Introduction to Hilbert Space and the theory of Spectral Multiplicity;Halmos,1951
4. General Theory of Banach Algebras;Rickart,1960
5. Theory of Groups and Quantum Mechanics;Weyl,1950