APA (7th ed.) Citation

Kropotkine , P., MONTAGU Ashley, & Huxley , T. H. (1955). Mutual aid: A factor of evolution. extending horizons books.

Chicago Style (17th ed.) Citation

Kropotkine , Pierre, MONTAGU Ashley, and Thomas Henry Huxley. Mutual Aid: A Factor of Evolution. extending horizons books, 1955.

MLA (8th ed.) Citation

Kropotkine , Pierre, et al. Mutual Aid: A Factor of Evolution. extending horizons books, 1955.