Cita APA (7th ed.)

Stephenson, H., Dummett, P., & Hughes, J. (2013). Life: Intermediate. Student's Book (1a. ed.). National Geographic Learning.

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

Stephenson, Helen, et al. Life: Intermediate. Student's Book. 1a. ed. National Geographic Learning, 2013.