1. R.J. Aumann, and L.S. Shapley, Values of Eon-Atomic Games, Princeton, 1974.
2. On two-dimensional Bernstein polynomials;Butzer;Canadian J. Math.,1953
3. Functional Analysis and Semigroups;Hille;Amer. Math. Soc. Colloq. Publ.,1957
4. C. Kingsley, Bernstein polynomials for functions of two variables of class C(K), Proc. Amer. Math. Soc. 2 (1951), 543–554.