@article{JDM_1891__2_144392,
     author = {E. Study},
     title = {Ueber die sph\"arische {Trigonometrie.}},
     journal = {Jahresbericht der Deutschen Mathematiker-Vereinigung},
     pages = {72--74},
     publisher = {mathdoc},
     volume = {2},
     year = {1891},
     zbl = {25.0798.01},
     url = {http://geodesic.mathdoc.fr/item/JDM_1891__2_144392/}
}