Cita APA (7a ed.)

Stephenson, H., Dummett, P., & Hughes, J. (2014). Life: Beginner. Student's book (1a. ed.). National Geographic Learning.

Cita Chicago Style (17a ed.)

Stephenson, Helen, Paul Dummett, y John Hughes. Life: Beginner. Student's Book. 1a. ed. Hampshire: National Geographic Learning, 2014.

Cita MLA (9a ed.)

Stephenson, Helen, et al. Life: Beginner. Student's Book. 1a. ed. National Geographic Learning, 2014.