@article{NSJOM_2000_30_1a_9,
     author = {R. 

 To\v{s}i\'c and L. \v{C}omi\'c},
     title = {On 

 set-valued non-boolean functions},
     journal = {Novi Sad Journal of Mathematics},
     pages = {79-88},
     publisher = {mathdoc},
     volume = {30},
     number = {1},
     year = {2000},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_2000_30_1a_9/}
}