Cita APA (7a ed.)

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.