Gaya APA

The World book encyclopedia W-X-Y-Z (Volume 21). (1978). : World Book Childcraft International.

Gaya Chicago

The World book encyclopedia W-X-Y-Z (Volume 21). . : World Book Childcraft International, 1978. Text.

Gaya MLA

The World book encyclopedia W-X-Y-Z (Volume 21). . : World Book Childcraft International, 1978. Text.

Gaya Turabian

The World book encyclopedia W-X-Y-Z (Volume 21). : World Book Childcraft International, 1978. Print.