Clarke, F.H., et al <br/><br/>
Nonsmooth analysis & control theory 
F.H. Clarke, et al 
 - New York  Springer  1998 
 - xii  276 
 - Graduate texts in mathematics 178 .
<br/><br/><label>ISBN: </label>9780387983363 
<br/><br/><label>Dewey Class. No.: </label>15.01+15.04  / CLAR