Cita APA (7th ed.)

Dummett, P., Hughes, J., & Stephenson, H. (2013). Life: Upper intermediate. Student book (1a. ed.). National Geographic.

Cita Chicago (17th ed.)

Dummett, Paul, John Hughes, i Helen Stephenson. Life: Upper Intermediate. Student Book. 1a. ed. Hampshire: National Geographic, 2013.

Cita MLA (9th ed.)

Dummett, Paul, et al. Life: Upper Intermediate. Student Book. 1a. ed. National Geographic, 2013.