Bald, W. Active Grammar.
Cita Chicago (17th ed.)Bald, W-D. Active Grammar. Hong Kong : Longman.
Cita MLA (8th ed.)Bald, W-D. Active Grammar.
Atenció: Aquestes cites poden no estar 100% correctes.
Cita APA (7th ed.)
Bald, W. Active Grammar.
Cita Chicago (17th ed.)Bald, W-D. Active Grammar. Hong Kong : Longman.
Cita MLA (8th ed.)Bald, W-D. Active Grammar.