1. O. Alvarez, E.N. Barron, H. Ishii, Hopf formulas for semicontinuous data, Indiana University Mathematical Journal, Vol. 48, No. 3 (1999).
2. M. Bardi, L.C. Evans, On Hopf’s formulas for solutions of Hamilton-Jacobi equations, Nonlinear Anal., TMA 8 (1984).
3. M. Bardi, I. Capuzzo DolcettaOptimal Control and Viscosity Solutions of HamiltonJacobi-Gellman EquationsSystems & Control: Foundations and Applications, Birkhäuser Verlag (1997).
4. G. BarlesSolutions de Viscosité des Equations de Hamilton-JacobiMathématiques et Applications, 17, Springer-Verlag (1994).
5. E.N. Barron, R. Jensen, Semicontinuous viscosity solutions for Hamilton-Jacobi equations with convex Hamiltonians, Comm PDE 15 (1990).