1. Embedding trees in the rationals;Baumgartner;Proceedings of the National Academy of Sciences the United States of America,1970
2. Conservative extensions of models of arithmetic;Blass;Archiv fur Mathematische Logik und Grundlagenforschung,1980
3. Model Theory;Chang,1973
4. From bounded arithmetic to second order arithmetic via automorphisms;Enayat,2006
5. Models and types of Peano’s arithmetic;Gaifman;Annals of Mathematical Logic,1976