@article{ZR_1998_8_16_a0, author = {Bogoljub Stankovi\'c}, title = {Preface}, journal = {Zbornik radova}, pages = {3 }, year = {1998}, volume = {8}, number = {16}, url = {http://geodesic.mathdoc.fr/item/ZR_1998_8_16_a0/} }