@article{AMLG_1972__15_137870,
     author = {Horst Osswald},
     title = {Homomorphe-invariante {Formeln} in der intuitionistischen {Logik.}},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {86--96},
     publisher = {mathdoc},
     volume = {15},
     year = {1972},
     zbl = {0251.02031},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1972__15_137870/}
}