1. Computability, An Introduction to Recursive Function Theory (Cambridge University Press, 1980).
2. The recursive irrationality of π
3. and , An Introduction to the Theory of Numbers (Oxford University Press, 1980).
4. Ingenuity in Mathematics, 6th printing (Mathematical Association of America, 1998).
5. Ueber die angen�herte Darstellung der Zahlen durch rationale Br�che