@article{GDZPPN002036568, title = {On midpoint convex set-valued functions.}, journal = {Aequationes mathematicae}, volume = {33}, year = {1987}, pages = {46-56}, zbl = {0639.39012}, url = {http://dml.mathdoc.fr/item/GDZPPN002036568} }
Nikodem, Kazimierz. On midpoint convex set-valued functions.. Aequationes mathematicae, Tome 33 (1987) pp. 46-56. http://gdmltest.u-ga.fr/item/GDZPPN002036568/