-. The New Book of Knowledge, Volume 20 W-X-Y-Z. Grolier.
Chicago Style (17th ed.) Citation-. The New Book of Knowledge, Volume 20 W-X-Y-Z. Grolier.
MLA (8th ed.) Citation-. The New Book of Knowledge, Volume 20 W-X-Y-Z. Grolier.
Warning: These citations may not always be 100% accurate.