APA (7th ed.) Citation

Barnum, P. T. (1866). The humbugs of the world. J. C. Hotten.

Chicago Style (17th ed.) Citation

Barnum, P. T. The Humbugs of the World. London: J. C. Hotten, 1866.

MLA (9th ed.) Citation

Barnum, P. T. The Humbugs of the World. J. C. Hotten, 1866.