Cita APA (7a ed.)

Crewe, R. J., Hildebrand, W., & Massey, D. (1989). Our world: Discovering patterns in physical geography. Heath.

Cita Chicago Style (17a ed.)

Crewe, R. James, William Hildebrand, y Donald Massey. Our World: Discovering Patterns in Physical Geography. Toronto: Heath, 1989.

Cita MLA (9a ed.)

Crewe, R. James, et al. Our World: Discovering Patterns in Physical Geography. Heath, 1989.