@article{PDA_1978_8_1_a1,
     author = {Dragutin Djurovi\'c},
     title = {Sur l},
     journal = {Publications of the Department of Astronomy},
     pages = {37 - 42},
     publisher = {mathdoc},
     volume = {8},
     number = {1},
     year = {1978},
     url = {http://geodesic.mathdoc.fr/item/PDA_1978_8_1_a1/}
}