APA (7th ed.) Citation

Long, C. T. (1965). Elementary introduction to number theory. D. C. Heath and Company.

Chicago Style (17th ed.) Citation

Long, Calvin T. Elementary Introduction to Number Theory. Boston: D. C. Heath and Company, 1965.

MLA (9th ed.) Citation

Long, Calvin T. Elementary Introduction to Number Theory. D. C. Heath and Company, 1965.