APA (7th ed.) Citation

(2013). The world book encyclopedia volume 20 - U - V. World Book.

Chicago Style (17th ed.) Citation

The World Book Encyclopedia Volume 20 - U - V. Chicago: World Book, 2013.

MLA (9th ed.) Citation

The World Book Encyclopedia Volume 20 - U - V. World Book, 2013.

Warning: These citations may not always be 100% accurate.