APA (7th ed.) Citation

Flesch, R. (1951). How to test readability ([First edition].). Harper.

Chicago Style (17th ed.) Citation

Flesch, Rudolf. How to Test Readability. [First edition]. New York: Harper, 1951.

MLA (9th ed.) Citation

Flesch, Rudolf. How to Test Readability. [First edition]. Harper, 1951.

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