Murphy, R. (1994). Essential grammar in use (1a. ed.). Cambridge university press.
Cita Chicago (17th ed.)Murphy, Raymond. Essential Grammar in Use. 1a. ed. Madrid: Cambridge university press, 1994.
Cita MLA (9th ed.)Murphy, Raymond. Essential Grammar in Use. 1a. ed. Cambridge university press, 1994.
Atenció: Aquestes cites poden no estar 100% correctes.