@article{GDZPPN002046032,
title = {Coding in the existential theory of concatenation.},
journal = {Archiv f\"ur mathematische Logik und Grundlagenforschung},
volume = {26},
year = {1987},
pages = {101-108},
zbl = {0646.03040},
url = {http://dml.mathdoc.fr/item/GDZPPN002046032}
}
Büchi, J. R.; Senger, St. Coding in the existential theory of concatenation.. Archiv für mathematische Logik und Grundlagenforschung, Tome 26 (1987) pp. 101-108. http://gdmltest.u-ga.fr/item/GDZPPN002046032/