@article{GDZPPN00204451X,
title = {A note on undecidable extensions of monadic second order successor arithmetic.},
journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
volume = {17},
year = {1975},
pages = {43-44},
zbl = {0325.02032},
url = {http://dml.mathdoc.fr/item/GDZPPN00204451X}
}
Thomas, Wolfgang. A note on undecidable extensions of monadic second order successor arithmetic.. Archiv für mathematische Logik und Grundlagenforschung, Tome 17 (1975) pp. 43-44. http://gdmltest.u-ga.fr/item/GDZPPN00204451X/