@article{JRAM_1930__163_149738,
     author = {Erich Sch\"onhardt},
     title = {\"Uber lateinische {Quadrate} und {Unionen.}},
     journal = {Journal f\"ur die reine und angewandte Mathematik},
     pages = {183--230},
     publisher = {mathdoc},
     volume = {163},
     year = {1930},
     url = {http://geodesic.mathdoc.fr/item/JRAM_1930__163_149738/}
}