Alexander, L. (1992). Step by step 1: Graded grammar practice for beginners (3a. ed.). Longman.
Cita Chicago Style (17a ed.)Alexander, L.G. Step by Step 1: Graded Grammar Practice for Beginners. 3a. ed. New York: Longman, 1992.
Cita MLA (8a ed.)Alexander, L.G. Step by Step 1: Graded Grammar Practice for Beginners. 3a. ed. Longman, 1992.
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