Cita APA (7a ed.)

Obee, B. (1998). Cambridge first certificate: Grammar and usage. Cambridge University Press.

Cita Chicago Style (17a ed.)

Obee, Bob. Cambridge First Certificate: Grammar and Usage. Cambridge: Cambridge University Press, 1998.

Cita MLA (8a ed.)

Obee, Bob. Cambridge First Certificate: Grammar and Usage. Cambridge University Press, 1998.