APA (7th ed.) Citation

Hardy, G. H. (1971). Introduction to the theory of numbers (4th.). English Language book society.

Chicago Style (17th ed.) Citation

Hardy, G. H. Introduction to the Theory of Numbers. 4th. London: English Language book society, 1971.

MLA (9th ed.) Citation

Hardy, G. H. Introduction to the Theory of Numbers. 4th. English Language book society, 1971.