Cita APA (7a ed.)
O'Driscoll, J. (1990). Penguin Basic English Grammar: Exercises (1. ed.). Penguin Books.
Cita Chicago Style (17a ed.)
O'Driscoll, James. Penguin Basic English Grammar: Exercises. 1. ed. London: Penguin Books, 1990.
Cita MLA (9a ed.)
O'Driscoll, James. Penguin Basic English Grammar: Exercises. 1. ed. Penguin Books, 1990.
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