APA (7th ed.) Citation

Guy, R. K. (2004). Unsolved problems in number theory / Richard K. Guy (3rd ed.). Springer.

Chicago Style (17th ed.) Citation

Guy, Richard K. Unsolved Problems in Number Theory / Richard K. Guy. 3rd ed. New York ; London: Springer, 2004.

MLA (9th ed.) Citation

Guy, Richard K. Unsolved Problems in Number Theory / Richard K. Guy. 3rd ed. Springer, 2004.

Warning: These citations may not always be 100% accurate.