1. J.E. Baumgartner, Iterated forcing, in: A.R.D. Mathias (Ed.), Surveys in Set Theory, Cambridge University Press, Cambridge, 1983, pp. 1–59.
2. E. Fried, J. Kollár, Automorphism groups of fields, in: E.T. Schmidt et al. (Eds.), Universal Algebra, Colloq. Math. Soc. János Bolyai, vol. 24, 1981, pp. 293–304.
3. W. Hodges, Model theory, Encyclopedia of Mathematics and its Applications, vol. 42, Cambridge University Press, Cambridge, 1993.
4. Automorphism towers of polycyclic groups;Hulse;J. Algebra,1970
5. Automorphisms of ω1-trees;Jech;Trans. Amer. Math. Soc.,1972