Cita APA (7a ed.)

Alexander, L. G. (1977). New Concept English. Practice and progress. Longman.

Cita Chicago Style (17a ed.)

Alexander, L. G. New Concept English. Practice and Progress. Londres: Longman, 1977.

Cita MLA (9a ed.)

Alexander, L. G. New Concept English. Practice and Progress. Longman, 1977.