Cita APA (7th ed.)

Boehm, R. G., Armstrong, D. G., & Hunkins, F. P. Geography: The world and its people.

Cita Chicago (17th ed.)

Boehm, Richard G., David G. Armstrong, i Francis P. Hunkins. Geography: The World and Its People.

Cita MLA (8th ed.)

Boehm, Richard G., et al. Geography: The World and Its People.