Cita APA (7th ed.)

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

Cita Chicago (17th ed.)

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

Cita MLA (9th ed.)

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