@article{AMLG_1975__17_137902,
     author = {Wolfgang Thomas},
     title = {A note on undecidable extensions of monadic second order successor arithmetic.},
     journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
     pages = {43--44},
     publisher = {mathdoc},
     volume = {17},
     year = {1975},
     zbl = {0325.02032},
     url = {http://geodesic.mathdoc.fr/item/AMLG_1975__17_137902/}
}