(2001). The World book encyclopedia: W-X-Y-Z V.21. World book, Inc.
Trích dẫn kiểu ChicagoThe World Book Encyclopedia: W-X-Y-Z V.21. World book, Inc, 2001.
MLA引文The World Book Encyclopedia: W-X-Y-Z V.21. World book, Inc, 2001.
警告：这些引文格式不一定是100％准确.
APA引文