APA (7th ed.) Citation

Encyclopaedia Inc. (1989). Encyclopaedia Britannica: Index to Volumes 1 to 23. Encyclopaedia Inc.

Chicago Style (17th ed.) Citation

Encyclopaedia Inc. Encyclopaedia Britannica: Index to Volumes 1 to 23. Chicago: Encyclopaedia Inc, 1989.

MLA (9th ed.) Citation

Encyclopaedia Inc. Encyclopaedia Britannica: Index to Volumes 1 to 23. Encyclopaedia Inc, 1989.

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