@article{GDZPPN002045125,
title = {Conservative extensions of models of arithmetic.},
journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
volume = {20},
year = {1980},
pages = {85-94},
zbl = {0453.03072},
url = {http://dml.mathdoc.fr/item/GDZPPN002045125}
}
Blass, Andreas. Conservative extensions of models of arithmetic.. Archiv für mathematische Logik und Grundlagenforschung, Tome 20 (1980) pp. 85-94. http://gdmltest.u-ga.fr/item/GDZPPN002045125/