Cita APA (7a ed.)

Abbs, B., & Freebairn, I. (1981). Developing Strategies. Students' Book. Strategies 3. Longman.

Cita Chicago Style (17a ed.)

Abbs, Brian, y Ingrid Freebairn. Developing Strategies. Students' Book. Strategies 3. Essex: Longman, 1981.

Cita MLA (9a ed.)

Abbs, Brian, y Ingrid Freebairn. Developing Strategies. Students' Book. Strategies 3. Longman, 1981.