@article{ZR_1977_2_10_a0,
     author = {Tatomir An{\dj}eli\'c},
     title = {Preface},
     journal = {Zbornik radova},
     pages = {7 },
     publisher = {mathdoc},
     volume = {2},
     number = {10},
     year = {1977},
     url = {http://geodesic.mathdoc.fr/item/ZR_1977_2_10_a0/}
}