%0 Journal Article %A Chien, Tran Quoc %T Duality and optimality conditions in abstract concave maximization %J Kybernetika %D 1985 %P 108-117 %V 21 %N 2 %I mathdoc %U http://geodesic.mathdoc.fr/item/KYB_1985__21_2_a2/ %G en %F KYB_1985__21_2_a2