@article{CM_1935__2__134_0,
     author = {Freudenthal, Hans},
     title = {Die {Hopfsche} {Gruppe.} {Eine} topologische {Begr\"undung} kombinatorischer {Begriffe}},
     journal = {Compositio Mathematica},
     pages = {134--162},
     publisher = {Johnson Reprint Corporation},
     volume = {2},
     year = {1935},
     zbl = {0011.27301},
     language = {de},
     url = {http://www.numdam.org/item/CM_1935__2__134_0/}
}