APA (7th ed.) Citation

World Book, Inc. (2005). World Book's encyclopedias of flags. World Book,Inc..

Chicago Style (17th ed.) Citation

World Book, Inc. World Book's Encyclopedias of Flags. Chicago: World Book,Inc., 2005.

MLA (9th ed.) Citation

World Book, Inc. World Book's Encyclopedias of Flags. World Book,Inc., 2005.

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