@article{01604182,
title = {Multifunctions with selections of convex and concave type.},
journal = {Mathematica Pannonica},
volume = {11},
year = {2000},
pages = {249-260},
zbl = {0973.26011},
language = {en},
url = {http://dml.mathdoc.fr/item/01604182}
}
Nikodem, Kazimierz; Páles, Zsolt; Wa̧sowicz, Szymon. Multifunctions with selections of convex and concave type.. Mathematica Pannonica, Tome 11 (2000) pp. 249-260. http://gdmltest.u-ga.fr/item/01604182/