@article{PIM_2013_N_S_94_108_a1,
     author = {Vladimir Dragovi\'c and Milena Radnovi\'c},
     title = {Minkowski {Plane,} {Confocal} {Conics,} and {Billiards}},
     journal = {Publications de l'Institut Math\'ematique},
     pages = {17 },
     publisher = {mathdoc},
     volume = {_N_S_94},
     number = {108},
     year = {2013},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/PIM_2013_N_S_94_108_a1/}
}