THE WORLD BOOK ENCYCLOPEDIA. (1989). The world book encyclopedia: Research guide/index. World Book.
Cita Chicago (17th ed.)THE WORLD BOOK ENCYCLOPEDIA. The World Book Encyclopedia: Research Guide/index. Chicago: World Book, 1989.
Cita MLA (9th ed.)THE WORLD BOOK ENCYCLOPEDIA. The World Book Encyclopedia: Research Guide/index. World Book, 1989.
Atenció: Aquestes cites poden no estar 100% correctes.