@article{MZ_1924__20_167801,
     author = {T. Kubota},
     title = {Eine {Ungleichheit} f\"ur die {Eilinien}},
     journal = {Mathematische Zeitschrift},
     pages = {264--266},
     publisher = {mathdoc},
     volume = {20},
     year = {1924},
     zbl = {50.0488.07},
     url = {http://geodesic.mathdoc.fr/item/MZ_1924__20_167801/}
}