Cita APA (7a ed.)

THE WORLD BOOK.. (2007). The world book W-X-Y-Z volume 21. World Book.

Cita Chicago Style (17a ed.)

THE WORLD BOOK.. The World Book W-X-Y-Z Volume 21. Chicago: World Book, 2007.

Cita MLA (9a ed.)

THE WORLD BOOK.. The World Book W-X-Y-Z Volume 21. World Book, 2007.