@article{ZR_2006_11_19_a0,
     author = {Bogoljub Stankovi\'c},
     title = {Preface},
     journal = {Zbornik radova},
     pages = {4 },
     publisher = {mathdoc},
     volume = {11},
     number = {19},
     year = {2006},
     url = {http://geodesic.mathdoc.fr/item/ZR_2006_11_19_a0/}
}