Cita APA (7th ed.)

Doff, A., & Becket, C. Listening 1 (4a ed.).

Cita Chicago (17th ed.)

Doff, Adrian, i Carolyn Becket. Listening 1. 4a ed.

Cita MLA (8th ed.)

Doff, Adrian, i Carolyn Becket. Listening 1. 4a ed.