@article{IM_1979__53_142667,
     author = {Katsuhiro Shiohama},
     title = {Busemann {Functions} and {Total} {Curvature.}},
     journal = {Inventiones mathematicae},
     pages = {281--297},
     publisher = {mathdoc},
     volume = {53},
     year = {1979},
     zbl = {0433.53050},
     url = {http://geodesic.mathdoc.fr/item/IM_1979__53_142667/}
}