DACOSTA, S. STEP UP ! WITH GRAMMAR- 7. FRANK EDUCATIONAL AIDS.
Cita Chicago (17th ed.)DACOSTA, STEPHEN. STEP UP ! WITH GRAMMAR- 7. NEW DELHI: FRANK EDUCATIONAL AIDS.
Cita MLA (9th ed.)DACOSTA, STEPHEN. STEP UP ! WITH GRAMMAR- 7. FRANK EDUCATIONAL AIDS.
Atenció: Aquestes cites poden no estar 100% correctes.