@article{AMLG_1969__12_137818,
     author = {Paul Lorenzen},
     title = {Theophrastische {Modallogik.}},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {72--75},
     publisher = {mathdoc},
     volume = {12},
     year = {1969},
     language = {de},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1969__12_137818/}
}