@article{MZ_1923__16_174956,
     author = {Fr. Levi},
     title = {Streckenkomplexe auf {Fl\"achen}},
     journal = {Mathematische Zeitschrift},
     pages = {148--158},
     year = {1923},
     volume = {16},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/MZ_1923__16_174956/}
}