1. La méthode de Fraissé dans les languages infinis;Calais;C.R. Acad. Sci. Paris,1969
2. Some remarks on the model theory of inifinitary languages;Chang,1968
3. L.Fuchs, Abelian Groups (Pergamon Press, New York, 1960).
4. I.Kaplansky, Infinite Abelian Groups, University of Michigan Press, Ann Arbor, 1968.
5. Finite Quantifier Equivalence;Karp,1965