@article{701903,
     title = {On the Clarke's generalized jacobian},
     booktitle = {Proceedings of the 14th Winter School on Abstract Analysis},
     series = {GDML\_Books},
     publisher = {Circolo Matematico di Palermo},
     address = {Palermo},
     year = {1987},
     pages = {[305]-307},
     mrnumber = {MR0920862},
     zbl = {0659.26008},
     url = {http://dml.mathdoc.fr/item/701903}
}

Fabian, M.; Preiss, D. On the Clarke’s generalized jacobian, dans Proceedings of the 14th Winter School on Abstract Analysis, GDML_Books,  (1987), pp. [305]-307. http://gdmltest.u-ga.fr/item/701903/