APA (7th ed.) Citation

Harris, Mower, & Sikorzynska. (2002). Opportunities: Pre-Intermediate (7th impression.). Longman.

Chicago Style (17th ed.) Citation

Harris, Mower, and Sikorzynska. Opportunities: Pre-Intermediate. 7th impression. Harlow: Longman, 2002.

MLA (8th ed.) Citation

Harris, et al. Opportunities: Pre-Intermediate. 7th impression. Longman, 2002.