APA (7th ed.) Citation

Humble, R., & Hook, R. (1990). The Travels of Marco Polo. Franklin Watts.

Chicago Style (17th ed.) Citation

Humble, Richard, and Richard Hook. The Travels of Marco Polo. London: Franklin Watts, 1990.

MLA (9th ed.) Citation

Humble, Richard, and Richard Hook. The Travels of Marco Polo. Franklin Watts, 1990.