Cita APA (7a ed.)

Falla, T. New Headway: English course beginner workbook whithout key. 2002.

Cita Chicago Style (17a ed.)

Falla, Tim. New Headway: English Course Beginner Workbook Whithout Key. Estados Unidos Offord University Press: 2002.

Cita MLA (9a ed.)

Falla, Tim. New Headway: English Course Beginner Workbook Whithout Key. 2002.