@article{MZ_1951__55_169259,
     author = {Wilhelm Klingenberg},
     title = {\"Uber das {Einspannungsproblem} in der projektiven und affinen {Differentialgeometrie.}},
     journal = {Mathematische Zeitschrift},
     pages = {321--345},
     year = {1951},
     volume = {55},
     zbl = {0046.39601},
     url = {http://geodesic.mathdoc.fr/item/MZ_1951__55_169259/}
}