Cita APA (7a ed.)

Walker, E., & Elsworth, S. (1989). Blueprint intermediate: Workbook.

Cita Chicago Style (17a ed.)

Walker, Elaine, y Steve Elsworth. Blueprint Intermediate: Workbook. Harlow, 1989.

Cita MLA (9a ed.)

Walker, Elaine, y Steve Elsworth. Blueprint Intermediate: Workbook. 1989.