@article{AMI_2017_47_a7,
     author = {Riku Kl\'en},
     title = {Hyperbolic distance between hyperbolic lines},
     journal = {Annales mathematicae et informaticae},
     pages = {129--139},
     year = {2017},
     volume = {47},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/AMI_2017_47_a7/}
}