@article{CMH_1992__67_3_140268,
     author = {Enrico Leuzinger},
     title = {On the trigonometry of symmetric spaces.},
     journal = {Commentarii mathematici Helvetici},
     pages = {252--286},
     publisher = {mathdoc},
     volume = {67},
     number = {3},
     year = {1992},
     zbl = {0779.53035},
     url = {http://geodesic.mathdoc.fr/item/CMH_1992__67_3_140268/}
}