1. Unbounded spectral operators;Bade, William G.;Pacific J. Math.,1954
2. Weak and strong limits of spectral operators;Bade, William G.;Pacific J. Math.,1954
3. On Boolean algebras of projections and algebras of operators;Bade, William G.;Trans. Amer. Math. Soc.,1955
4. A multiplicity theory for Boolean algebras of projections in Banach spaces;Bade, William G.;Trans. Amer. Math. Soc.,1959
5. N. Bourbaki, Eléments de mathématique. V, Livre III, Chapitre VIII (No. 1029) Paris, Hermann, 1947.