@article{10_4064_aa_77_1_9_21,
     author = {Stefan Breulmann and Volker Helmke},
     title = {The covolume of quaternion groups on the four-dimensional hyperbolic space},
     journal = {Acta Arithmetica},
     pages = {9--21},
     publisher = {mathdoc},
     volume = {77},
     number = {1},
     year = {1996},
     doi = {10.4064/aa-77-1-9-21},
     language = {en},
     url = {http://geodesic.mathdoc.fr/articles/10.4064/aa-77-1-9-21/}
}