@article{KJM_2005_28_a9,
     author = {Emilija Ne\v{s}ovi\'c},
     title = {Hyperbolic angle function in the {Lorentzian} plane},
     journal = {Kragujevac Journal of Mathematics},
     pages = {139 },
     publisher = {mathdoc},
     volume = {28},
     year = {2005},
     zbl = {1120.53305},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/KJM_2005_28_a9/}
}