Gaya APA

The World Book Encyclopedia U,V Volume 20. (2007). Chicago: World Book Inc..

Gaya Chicago

The World Book Encyclopedia U,V Volume 20. . Chicago: World Book Inc., 2007. Text.

Gaya MLA

The World Book Encyclopedia U,V Volume 20. . Chicago: World Book Inc., 2007. Text.

Gaya Turabian

The World Book Encyclopedia U,V Volume 20. Chicago: World Book Inc., 2007. Print.