1. Optimal Control and Viscosity Solutions of Hamilton–Jacobi–Bellman Equations;Bardi,1997
2. F.H. Clarke, Optimization and Nonsmooth Analysis, Wiley-Interscience, New York, 1983; Republished as Classics in Applied Mathematics, vol. 5, SIAM, Philadelphia, 1990.
3. Complements, approximations, smoothings and invariance properties;Clarke;J. Convex Anal.,1997
4. Qualitative properties of trajectories of control systems;Clarke;J. Dyn. Control Syst.,1995
5. F.H. Clarke, Yu.S. Ledyaev, R.J. Stern, P.R. Wolenski, Nonsmooth Analysis and Control Theory, vol. 178, Graduate Texts in Mathematics, Springer, New York, 1998.