Citazione Stile APA (7a Edizione)

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

Citazione stile Chigago Style (17a edizione)

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

Citatione MLA (8a ed.)

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