@article{MV_1970_22_3_a0,
     author = {R. Daci\'c},
     title = {The sine functional equation for groups},
     journal = {Matemati\v{c}ki vesnik},
     pages = {279 },
     publisher = {mathdoc},
     volume = {22},
     number = {3},
     year = {1970},
     url = {http://geodesic.mathdoc.fr/item/MV_1970_22_3_a0/}
}