@article{GDZPPN002043319,
title = {Recursively enumerable classes and their application to recursive sequences of formal theories.},
journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
volume = {8},
year = {1965},
pages = {104-121},
zbl = {0242.02046},
url = {http://dml.mathdoc.fr/item/GDZPPN002043319}
}
Pour-El, Boykan; Marian; Putnam, Hilary. Recursively enumerable classes and their application to recursive sequences of formal theories.. Archiv für mathematische Logik und Grundlagenforschung, Tome 8 (1965) pp. 104-121. http://gdmltest.u-ga.fr/item/GDZPPN002043319/