APA (7th ed.) Citation

Twain, M. (1917). What is man?: And other essays. Harper & Brothers Publishers.

Chicago Style (17th ed.) Citation

Twain, Mark. What Is Man?: And Other Essays. New York: Harper & Brothers Publishers, 1917.

MLA (9th ed.) Citation

Twain, Mark. What Is Man?: And Other Essays. Harper & Brothers Publishers, 1917.

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