1. Numerical ranges…;Bonsall,1971
2. Dually irreducible representations of Banach algebras;Bonsall;Quart. J. Math. Oxford Ser.,1968
3. Geometrical properties of the unit sphere of Banach algebras;Bohnenblust;Ann. of Math.,1955
4. On an inequality of Banach algebra geometry and semi-inner-product theory;Glickfeld;Illinois J. Math.,1970
5. Functional analysis and semi-groups;Hille,1957