APA (7th ed.) Citation

Dellar, H., & Walkley, A. (2016). Outcomes: Pre-Intermediate Student's Book. National Geographic Learning; Cengage Learning.

Chicago Style (17th ed.) Citation

Dellar, Hugh, and Andrew Walkley. Outcomes: Pre-Intermediate Student's Book. United Kingdom: National Geographic Learning; Cengage Learning, 2016.

MLA (9th ed.) Citation

Dellar, Hugh, and Andrew Walkley. Outcomes: Pre-Intermediate Student's Book. National Geographic Learning; Cengage Learning, 2016.