Cita APA (7a ed.)

Frazier, L., & Mills, R. Northstar: Listening and speaking (3a ed.).

Cita Chicago Style (17a ed.)

Frazier, Laurice, y Robin Mills. Northstar: Listening and Speaking. 3a ed.

Cita MLA (8a ed.)

Frazier, Laurice, y Robin Mills. Northstar: Listening and Speaking. 3a ed.