Aharon Ben-Tal, Jochem Zowe. Necessary and sufficient optimality conditions for a class of nonsmooth minimization problems. Math. Program., 24(1):70-91, 1982. [doi]
@article{Ben-TalZ82,
title = {Necessary and sufficient optimality conditions for a class of nonsmooth minimization problems},
author = {Aharon Ben-Tal and Jochem Zowe},
year = {1982},
doi = {10.1007/BF01585095},
url = {http://dx.doi.org/10.1007/BF01585095},
researchr = {https://researchr.org/publication/Ben-TalZ82},
cites = {0},
citedby = {0},
journal = {Math. Program.},
volume = {24},
number = {1},
pages = {70-91},
}