APA (7th ed.) Citation

(1981). The new encyclopaedia Britannica. Encyclopaedia Britannica, Inc.

Chicago Style (17th ed.) Citation

The New Encyclopaedia Britannica. Encyclopaedia Britannica, Inc, 1981.

MLA (8th ed.) Citation

The New Encyclopaedia Britannica. Encyclopaedia Britannica, Inc, 1981.

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