Cita APA (7a ed.)

Pearce, F., & Puddifoot, A. (2008). Earth then and now: Amazing images of our changing world. Firefly Books.

Cita Chicago Style (17a ed.)

Pearce, Fred, y Andrew Puddifoot. Earth Then and Now: Amazing Images of Our Changing World. Buffalo, N.Y.: Firefly Books, 2008.

Cita MLA (8a ed.)

Pearce, Fred, y Andrew Puddifoot. Earth Then and Now: Amazing Images of Our Changing World. Firefly Books, 2008.

Precaución: Estas citas no son 100% exactas.