Cita APA (7th ed.)
World Book, Inc. (1992). The World Book Encyclopedia: W-X-Y-Z - Volume -21. World Book, Inc.
Cita Chicago (17th ed.)
World Book, Inc. The World Book Encyclopedia: W-X-Y-Z - Volume -21. Chicago: World Book, Inc, 1992.
Cita MLA (9th ed.)
World Book, Inc. The World Book Encyclopedia: W-X-Y-Z - Volume -21. World Book, Inc, 1992.
Atenció: Aquestes cites poden no estar 100% correctes.