Cita APA (7a ed.)

Alexander, L., & Bailey, T. P. (1971). First things first students' book: An integrated course for beginners.

Cita Chicago Style (17a ed.)

Alexander, L.G, y Tom Pettengell Bailey. First Things First Students' Book: An Integrated Course for Beginners. London, 1971.

Cita MLA (9a ed.)

Alexander, L.G, y Tom Pettengell Bailey. First Things First Students' Book: An Integrated Course for Beginners. 1971.