@article{COCV_2001__6__593_0,
     author = {Rifford, Ludovic},
     title = {On the existence of nonsmooth {control-Lyapunov} functions in the sense of generalized gradients},
     journal = {ESAIM: Control, Optimisation and Calculus of Variations},
     pages = {593--611},
     publisher = {EDP-Sciences},
     volume = {6},
     year = {2001},
     mrnumber = {1872388},
     zbl = {1002.93058},
     language = {en},
     url = {http://archive.numdam.org/item/COCV_2001__6__593_0/}
}