Cita APA (7a ed.)

Ballard, M., Mathias, P., Floyd, G., & Jordan, S. (1971). The world at war: 1900 - 1918. Methuen.

Cita Chicago Style (17a ed.)

Ballard, Martin, Peter Mathias, Gareth Floyd, y Stuart Jordan. The World at War: 1900 - 1918. London [u.a.]: Methuen, 1971.

Cita MLA (9a ed.)

Ballard, Martin, et al. The World at War: 1900 - 1918. Methuen, 1971.