@article{AFM_2017_42_1_a25,
     author = {Riku Kl\'en and Antti Rasila and Jarno Talponen},
     title = {On the smoothness of quasihyperbolic balls},
     journal = {Annales Fennici Mathematici},
     pages = {439--452},
     publisher = {mathdoc},
     volume = {42},
     number = {1},
     year = {2017},
     doi = {10.5186/aasfm.2017.4226},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.5186/aasfm.2017.4226/}
}