Cita APA (7a ed.)

Ashworth, J., & Clark, J. (1997). New stepping stones: Activity book (1ª ed.).

Cita Chicago Style (17a ed.)

Ashworth, Julie, y John Clark. New Stepping Stones: Activity Book. 1ª ed. Edinburgh, 1997.

Cita MLA (9a ed.)

Ashworth, Julie, y John Clark. New Stepping Stones: Activity Book. 1ª ed. 1997.