APA (7th ed.) Citation

Twain, M. (1917). Mark Twain's letters. Harper.

Chicago Style (17th ed.) Citation

Twain, Mark. Mark Twain's Letters. New York [u.a.]: Harper, 1917.

MLA (9th ed.) Citation

Twain, Mark. Mark Twain's Letters. Harper, 1917.

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