@article{MZ_1969__112_171225,
     author = {Stefan Hildebrandt},
     title = {\"Uber {Fl\"achen} konstanter mittlerer {Kr\"ummung.}},
     journal = {Mathematische Zeitschrift},
     pages = {107--144},
     publisher = {mathdoc},
     volume = {112},
     year = {1969},
     zbl = {0183.39501},
     url = {http://geodesic.mathdoc.fr/item/MZ_1969__112_171225/}
}