Cita APA (7a ed.)

Abbs, B., & Freebairn, I. (1989). Blueprint: Intermediate. Longman.

Cita Chicago Style (17a ed.)

Abbs, Brian, y Ingrid Freebairn. Blueprint: Intermediate. England: Longman, 1989.

Cita MLA (8a ed.)

Abbs, Brian, y Ingrid Freebairn. Blueprint: Intermediate. Longman, 1989.