1. Models and Ultraproducts;Bell,1969
2. Chang Keisler, Model Theory, to appear.
3. Uber eine Verallgemeinerung der Robinsonschen Modelverstandigung;Kaier;I. Zeit. Math. Logic und Grund. der Math.,1969
4. Diaphantine equations in non-standard models of arithmetics;Rabin,1962
5. Introduction to Model Theory and to the Metamathematics of Algebra;Robinson,1963