@article{NSJOM_1992_22_2a_4,
     author = {Had\v{z}i\'c 

 Olga},
     title = {A theorem on best 

 approximations and applications},
     journal = {Novi Sad Journal of Mathematics},
     pages = {47-55},
     year = {1992},
     volume = {22},
     number = {2},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_1992_22_2a_4/}
}