Cita APA (7a ed.)

May, P., & Henderson, F. (1991). First choice for proficiency. Heinemann.

Cita Chicago Style (17a ed.)

May, Peter, y Felicity Henderson. First Choice for Proficiency. Oxford: Heinemann, 1991.

Cita MLA (8a ed.)

May, Peter, y Felicity Henderson. First Choice for Proficiency. Heinemann, 1991.