Andrew Adler. Extensions of non-standard models of number theory. Zeitschrift für mathematische Logik und Grundlagen der Mathematik, vol. 15 (1969), pp. 289–290. - Haim Gaifman. A note on models and submodels of arithmetic. Conference in mathematical logic—London '70, edited by Wilfrid Hodges, Lecture notes in mathematics, no. 255, Springer-Verlag, Berlin, Heidelberg, and New York, 1972, pp. 128–144.
1975 ◽
Vol 40
(2)
◽
pp. 244-245