APA (7th ed.) Citation

Flesch, R. F. (1951). How to test readability ([1st ed.].). Harper.

Chicago Style (17th ed.) Citation

Flesch, Rudolf Franz. How to Test Readability. [1st ed.]. New York: Harper, 1951.

MLA (9th ed.) Citation

Flesch, Rudolf Franz. How to Test Readability. [1st ed.]. Harper, 1951.