Cita APA (7a ed.)

Harris, M., Sikorznska, A., & Mower, D. (2001). Opportunities elementary: Students' book. Pearson Education.

Cita Chicago Style (17a ed.)

Harris, Michael, Anna Sikorznska, y David Mower. Opportunities Elementary: Students' Book. Harlow: Pearson Education, 2001.

Cita MLA (8a ed.)

Harris, Michael, et al. Opportunities Elementary: Students' Book. Pearson Education, 2001.