Gaya APA

The World Book Encyclopedia (W-X-Y-Z Volume 21). (1972). USA: Field Enterprises Educational Corporation.

Gaya Chicago

The World Book Encyclopedia (W-X-Y-Z Volume 21). W-X-Y-Z Volume 21, 1972. USA: Field Enterprises Educational Corporation, 1972. Text.

Gaya MLA

The World Book Encyclopedia (W-X-Y-Z Volume 21). W-X-Y-Z Volume 21, 1972. USA: Field Enterprises Educational Corporation, 1972. Text.

Gaya Turabian

The World Book Encyclopedia (W-X-Y-Z Volume 21). USA: Field Enterprises Educational Corporation, 1972. Print.