@misc{NSJOM_2004_34_2a_15,
     title = {Some open 

 problems},
     journal = {Novi Sad Journal of Mathematics},
     pages = {187-190},
     year = {2004},
     volume = {34},
     number = {2},
     url = {http://geodesic.mathdoc.fr/item/NSJOM_2004_34_2a_15/}
}