Cita APA (7th ed.)

Quirk, R., & Stein, G. (1990). English in use. Longman.

Cita Chicago (17th ed.)

Quirk, Randolph, i Gabriele Stein. English in Use. Essex: Longman, 1990.

Cita MLA (9th ed.)

Quirk, Randolph, i Gabriele Stein. English in Use. Longman, 1990.