@article{MM2_1973__10_154178,
     author = {Rainer Walden},
     title = {Untermannigfaltigkieten mit paralleler zweiter {Fundamentalform} in euklidischen {R\"aumen} und {Sph\"aren.}},
     journal = {Manuscripta mathematica},
     pages = {91--102},
     publisher = {mathdoc},
     volume = {10},
     year = {1973},
     zbl = {0262.53038},
     url = {http://geodesic.mathdoc.fr/item/MM2_1973__10_154178/}
}