Abbs, B., & Freebairn, I. (1994). Blueprint one.: Students` book (1a. ed. 6a. imp.). Longman.

Abbs, Brian, and Ingrid Freebairn. Blueprint One.: Students` Book. 1a. ed. 6a. imp. Madrid: Longman, 1994.

Abbs, Brian, and Ingrid Freebairn. Blueprint One.: Students` Book. 1a. ed. 6a. imp. Longman, 1994.