@article{GDZPPN002316978, title = {The Family of Horospheres Through Two Points.}, journal = {Mathematische Annalen}, volume = {243}, year = {1979}, pages = {1-12}, zbl = {0379.53020}, url = {http://dml.mathdoc.fr/item/GDZPPN002316978} }
Im Hof, Hans Christoph. The Family of Horospheres Through Two Points.. Mathematische Annalen, Tome 243 (1979) pp. 1-12. http://gdmltest.u-ga.fr/item/GDZPPN002316978/