Cita APA (7a ed.)

Sommer, P., Heater, D., & Owen, G. (1979). Global problems (1. publ., reprinted and updated.). Harrap.

Cita Chicago Style (17a ed.)

Sommer, Peter, Derek Heater, y Gwyneth Owen. Global Problems. 1. publ., reprinted and updated. Walton-on-Thames, Surrey [u.a.]: Harrap, 1979.

Cita MLA (9a ed.)

Sommer, Peter, et al. Global Problems. 1. publ., reprinted and updated. Harrap, 1979.