@article{MET_1960__3_175089,
     author = {O. Ludwig},
     title = {\"Uber {Erwartungswerte} und {Varianzen} von {Ranggr\"o{\ss}en} in kleinen {Stichproben.}},
     journal = {Metrika},
     pages = {218--233},
     publisher = {mathdoc},
     volume = {3},
     year = {1960},
     zbl = {0095.13201},
     url = {http://geodesic.mathdoc.fr/item/MET_1960__3_175089/}
}