@article{AMLG_1960__5_137753,
     author = {Heinrich Behmann},
     title = {Das {Vereinfachungsproblem} f\"ur aussagenlogische {Normalformen.}},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {65--89},
     publisher = {mathdoc},
     volume = {5},
     year = {1960},
     zbl = {0117.01002},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1960__5_137753/}
}