Cita APA (7a ed.)

Maley, A., & Duff, A. (1978). Variations on a theme. Cambridge university.

Cita Chicago Style (17a ed.)

Maley, Alan, y Alan Duff. Variations on a Theme. Cambridge: Cambridge university, 1978.

Cita MLA (9a ed.)

Maley, Alan, y Alan Duff. Variations on a Theme. Cambridge university, 1978.