APA (7th ed.) Citation

Kropotkin, P. A., Montagu Ashley, & Huxley Thomas H. (1955). Mutual Aid. Extending Horizons Books.

Chicago Style (17th ed.) Citation

Kropotkin, Pëtr Alekseevič, Montagu Ashley, and Huxley Thomas H. Mutual Aid. Extending Horizons Books, 1955.

MLA (8th ed.) Citation

Kropotkin, Pëtr Alekseevič, et al. Mutual Aid. Extending Horizons Books, 1955.