1. Jordan homomorphisms of rings;Jacobson, N.;Trans. Amer. Math. Soc.,1950
2. The positive cone in Banach algebras;Kelley, J. L.;Trans. Amer. Math. Soc.,1953
3. On an inner characteristic of the set of all continuous functions defined on a bicompact Hausdorff space;Krein, Mark;C. R. (Doklady) Acad. Sci. URSS (N.S.),1940
4. Order in operator algebras;Sherman, S.;Amer. J. Math.,1951