\bibitem{Barwise} J. Barwise (editor), {\it Handbook of mathematical logic}, North-Holland, 1977.
\bibitem{CK} Chang and Keisler, {\it Continuous Model Theory}, Annals of Mathematical Studies, Princeton University Press, {\bf58} (1966).
\bibitem{CH} P. Cintula and P. H\'{a}jek, {\it Triangular norm based predicate fuzzy logics},
Fuzzy sets and systems, {\bf161} (2010), 311-346.
\bibitem{DE} P. Dellunde and F. Esteva, {\it On elementary extensions for fuzzy predicate logics},
In Proceedings of IPMU, (2010), 747-756.
\bibitem{G} G. Gerla, {\it The category of the fuzzy models and Lowenheim-Skolem theorem},
Mathematics of Fuzzy Systems, (1986), 121-141.
\bibitem{Hajek1} P. H\'{a}jek, {\it Metamathematics of Fuzzy Logic, Trends in Logic},
Kluwer Academic Publishers, Dordercht, {\bf4} (1998).
\bibitem{Hajek2} P. H\'{a}jek and P. Cintula, {\it On theories and models in fuzzy predicate logics},
Journal of Symbolic Logic, {\bf 71} (2006), 863-880.
\bibitem{Montagna} F. Montagna, {\it On the predicate logics of continuous t-norm BL-algebras},
Archive for Mathematical Logic, {\bf44} (2005), 97-114.
\bibitem{Yaacov} I. B. Yaacov, A. P. Pedersen, {\it A Proof of completeness for continnuous
first-order logic}, Journal of Symbolic Logic, {\bf75} (2010), 168-190.
\bibitem{YBHU} I. B. Yaacov, A. Berenstein, C. W. Henson and A. Usvyatsov,
{\it Model theory for metric structures}, In Model Theory with Applications to Algebra and Analysis,
Vol. II, eds. Z. Chatzidakis, D. Macpherson, A. Pillay, and A.Wilkie, Lecture Notes series
of the London Mathematical Society, No. 350, Cambridge University Press, (2008), 315-427.