@article{JCA_1999_6_2_JCA_1999_6_2_a1,
     author = {T. Pennanen},
     title = {Graph-Convex {Mappings} and {K-Convex} {Functions}},
     journal = {Journal of convex analysis},
     pages = {235--266},
     publisher = {mathdoc},
     volume = {6},
     number = {2},
     year = {1999},
     url = {http://geodesic.mathdoc.fr/item/JCA_1999_6_2_JCA_1999_6_2_a1/}
}