APA (7th ed.) Citation

Dummett, P., Dummett, P., Stephenson, H., & Lansford, L. (2016). Keynote intermediate: Level B1. National Geographic Learning.

Chicago Style (17th ed.) Citation

Dummett, Paul, Paul Dummett, Helen Stephenson, and Lewis Lansford. Keynote Intermediate: Level B1. Andover, Hampshire: National Geographic Learning, 2016.

MLA (9th ed.) Citation

Dummett, Paul, et al. Keynote Intermediate: Level B1. National Geographic Learning, 2016.