@article{1183745868,
author = {Butz, C. and Moerdijk, I.},
title = {An Elementary Definability Theorem for First Order Logic},
journal = {J. Symbolic Logic},
volume = {64},
number = {1},
year = {1999},
pages = { 1028-1036},
language = {en},
url = {http://dml.mathdoc.fr/item/1183745868}
}
Butz, C.; Moerdijk, I. An Elementary Definability Theorem for First Order Logic. J. Symbolic Logic, Tome 64 (1999) no. 1, pp. 1028-1036. http://gdmltest.u-ga.fr/item/1183745868/