(1992). The World Book Encyclopedia: Volume 20 ( U-V ). World Book, Inc..
Chicago Style (17th ed.) CitationThe World Book Encyclopedia: Volume 20 ( U-V ). London: World Book, Inc., 1992.
MLA (9th ed.) CitationThe World Book Encyclopedia: Volume 20 ( U-V ). World Book, Inc., 1992.
Warning: These citations may not always be 100% accurate.