APA (7th ed.) Citation

Hall, D., & Gregory, R. (1989). The Natural Health Book. Penguin Books.

Chicago Style (17th ed.) Citation

Hall, Dorothy, and Richard Gregory. The Natural Health Book. Australia: Penguin Books, 1989.

MLA (9th ed.) Citation

Hall, Dorothy, and Richard Gregory. The Natural Health Book. Penguin Books, 1989.

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