@article{10_4153_CJM_1993_065_x,
     author = {Clarke, F. H. and Stern, R. J. and Wolenski, P. R.},
     title = {Subgradient {Criteria} for {Monotonicity,} {The} {Lipschitz} {Condition,} and {Convexity}},
     journal = {Canadian journal of mathematics},
     pages = {1167--1183},
     year = {1993},
     volume = {45},
     number = {6},
     doi = {10.4153/CJM-1993-065-x},
     url = {http://geodesic.mathdoc.fr/articles/10.4153/CJM-1993-065-x/}
}