APA (7th ed.) Citation

Lankford, F. G. J., & Clark, J. R. (1961). Essential mathematics. Harcourt Brace and World.

Chicago Style (17th ed.) Citation

Lankford, Francis G. Jr, and J. R. Clark. Essential Mathematics. New York: Harcourt Brace and World, 1961.

MLA (9th ed.) Citation

Lankford, Francis G. Jr, and J. R. Clark. Essential Mathematics. Harcourt Brace and World, 1961.

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