"Nonstandard Models of Peano Arithmetic" (with S. Kochen), in "Logic and Algorithmic: International Symposium Held in Honor of Ernst Specker", H. Läuchli (ed.
«Nonstandard Models of Peano Arithmetic» (with S. Kochen), in "Logic and Algorithmics: International Symposium Held in Honor of Ernst Specker", H. Lauchli (ed.