1. Generalized gradients and applications;Clarke;Trans. Am. math. Soc.,1975
2. The maximum principle under minimal hypotheses;Clarke;SIAM J. Control Optim.,1976
3. Necessary conditions for a general control problem;Clarke,1976
4. Optimization and Nonsmooth Analysis;Clarke,1983
5. Theory of Ordinary Differential Equations;Coddington,1955