@article{GDZPPN002043041,
title = {Representability of recursively enumerable sets in formal theories.},
journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
volume = {5},
year = {1960},
pages = {119-127},
zbl = {0113.24305},
url = {http://dml.mathdoc.fr/item/GDZPPN002043041}
}
Shepherdson, J.C. Representability of recursively enumerable sets in formal theories.. Archiv für mathematische Logik und Grundlagenforschung, Tome 5 (1960) pp. 119-127. http://gdmltest.u-ga.fr/item/GDZPPN002043041/