Hardy, G. H., & Wright, E. M. (1979). Theory of Numbers: An introduction to the theory of numbers (5th ed.). Clarendon Press.

Hardy, G. H., and E. M. Wright. Theory of Numbers: An Introduction to the Theory of Numbers. 5th ed. Oxford: Clarendon Press, 1979.

Hardy, G. H., and E. M. Wright. Theory of Numbers: An Introduction to the Theory of Numbers. 5th ed. Clarendon Press, 1979.