@article{NSJOM_1993_23_1a_3,
     author = {Ding Xie Ping},
     title = {Weak conctrator 

 directions and weak directional constructions for a set valued operator with 

 a closed range},
     journal = {Novi Sad Journal of Mathematics},
     pages = {39-50},
     publisher = {mathdoc},
     volume = {23},
     number = {1},
     year = {1993},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1993_23_1a_3/}
}