@article{MOMA_1977__83_177812,
     author = {Curt Christian},
     title = {Eine {Note} zum {System} {PC.}},
     journal = {Monatshefte f\"ur Mathematik},
     pages = {191--200},
     year = {1977},
     volume = {83},
     zbl = {0362.02068},
     url = {http://geodesic.mathdoc.fr/item/MOMA_1977__83_177812/}
}