APA (7th ed.) Citation

Malthus, T. R., Huxley, J., & Osborn, F. J. (1960). On population: Three essays. New American Library.

Chicago Style (17th ed.) Citation

Malthus, T. R., Julian Huxley, and Frederic J. Osborn. On Population: Three Essays. New York: New American Library, 1960.

MLA (8th ed.) Citation

Malthus, T. R., et al. On Population: Three Essays. New American Library, 1960.