@article{MOMA_1951__55_176866,
     author = {Hans Robert M\"uller},
     title = {\"Uber geschlossene {Bewegungsvorg\"ange.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {206--214},
     publisher = {mathdoc},
     volume = {55},
     year = {1951},
     zbl = {0043.36503},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1951__55_176866/}
}