If I'm not mistaken, it was in his seminal paper “An Essentially Undecidable Axiom System”, published in

Proceedings of the International Congress of Mathematics (1950), 729–730,

where R.M. Robinson proved that Gödel Incompleteness Theorem still applies to Peano Axioms if we drop the induction schema (hence showing that infinite axiomatization is not necessary for essential undecidability), in what we now call Robinson Arithmetic.

I would like to know:

- Is actually this paper what I should be looking for?
- Can it be found anywhere on the net? (I already tried on MathSciNet, SpringerLink, JSTOR and Google Scholar, without success)
- Can anyone pinpoint to closely related, or at least similar, accessible papers?

(Note: I already have the book "Undecidable theories", which he published in collaboration with Tarski, but I'd prefer to locate papers about 'Robinson theory', specifically).

Variants of Robinson's essentially undecidable theory ${\rm R}$.MR0710365 - Vaught,On a theorem of Cobham concerning undecidable theories, MR0156788 – François G. Dorais♦ Jul 5 '10 at 20:24