1. Cabre, X., Caffarelli, L.A.: Fully nonlinear elliptic partial differential equations. American Mathematical Society (1997).
2. Caffarelli, L. A.: Interior estimates for fully nonlinear equations. Ann. of Math. 130, 189–213 (1989).
3. Peng, S.: Filtration Consistent Nonlinear Expectations and Evaluations of Contingent Claims, Acta Mathematicae Applicatae Sinica. Engl. Ser. 20(2), 1–24 (2004).
4. Peng, S.: Nonlinear expectations and nonlinear Markov chains. Chin. Ann. Math.26B(2), 159–184 (2005).
5. Peng, S.: G–Expectation, G–Brownian Motion and Related Stochastic Calculus of Itô’s type (2007). in Stochastic Analysis and Applications, The Abel Symposium 2005, Abel Symposia2, Edit. Benth et. al., 541–567, Springer-Verlag.