Cita APA (7a ed.)

Mortimer, C., & Gan, D. (1977). Contractions: A Pronunciation practice book. Cambridge University.

Cita Chicago Style (17a ed.)

Mortimer, Colin, y Daria Gan. Contractions: A Pronunciation Practice Book. Cambridge: Cambridge University, 1977.

Cita MLA (9a ed.)

Mortimer, Colin, y Daria Gan. Contractions: A Pronunciation Practice Book. Cambridge University, 1977.