APA (7th ed.) Citation

Twain, M., Clemens, S. L., & Anderson, F. (1979). A pen warmed-up in hell: Mark Twain in protest. Harper & Row, Publishers, Inc.

Chicago Style (17th ed.) Citation

Twain, Mark, Samuel Langhorne Clemens, and Frederick Anderson. A Pen Warmed-up in Hell: Mark Twain in Protest. New York, N.Y: Harper & Row, Publishers, Inc, 1979.

MLA (9th ed.) Citation

Twain, Mark, et al. A Pen Warmed-up in Hell: Mark Twain in Protest. Harper & Row, Publishers, Inc, 1979.