1. Asatryan, G.: On ordered fields with infinitely many integer parts, preprint (2008)
2. Ash C.J., Knight J.F.: Computable Structures and the Hyperarithmetical Hierarchy, Stud. Logic Found. Math, vol. 144. Elsevier, Amsterdam (2000)
3. Berarducci A., Otero M.: A recursive nonstandard model of normal Open induction. J. Symb. Logic 61, 1228–1241 (1996)
4. D’Aquino P., Knight J.F., Starchenko S.: Real closed fields and models of Peano arithmetic. J. Symb. Logic 75, 1–11 (2010)
5. Ershov, Yu.: A certain hierarchy of sets I, II, III, algebra and Logic, #1, vol. 7, pp. 47–74 (1968); #4, vol. 7, pp.15–47 (1968); #1, vol. 9, pp. 34–51 (1970)