[FOM] A question about references

[Arnon Avron]

In his recent posting about incompleteness Friedman quoted
the following from Scott Aaronson:

"(2)  Independence of statements in transfinite set theory, such as CH
and AC. Unlike "ordinaryâ" mathematical statements --- P ̸= NP, the Riemann
hypothesis, etc. the set-theoretic ones can't be rephrased in the
language of elementary arithmetic; only questions about their
provability from various axiom systems are arithmetical."

My question: what are the best sources in which the most
updated (and perhaps even not the most updated) rephrasing
of P ̸= NP, the Riemann hypothesis, etc in the 
language of elementary arithmetic can be found (and the
equivalences are proved)?

Thanks,

Arnon Avron