APA (7th ed.) Citation

(1991). The new Encyclopaedia Britannica. Encyclopaedia Britannica.

Chicago Style (17th ed.) Citation

The New Encyclopaedia Britannica. Chicago: Encyclopaedia Britannica, 1991.

MLA (9th ed.) Citation

The New Encyclopaedia Britannica. Encyclopaedia Britannica, 1991.

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