@article{JDM_1961__63_146481,
     author = {M. Pinl},
     title = {Zum {Gedenken} an {Robert} {Ritterl.}},
     journal = {Jahresbericht der Deutschen Mathematiker-Vereinigung},
     pages = {137--140},
     publisher = {mathdoc},
     volume = {63},
     year = {1961},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/JDM_1961__63_146481/}
}