MAS'UD, F. (1992). Essentials of English grammar: A practical guide.--Ed.2. BPFE.
Cita Chicago (17th ed.)MAS'UD, Fuad. Essentials of English Grammar: A Practical Guide.--Ed.2. Yogyakarta: BPFE, 1992.
Cita MLA (9th ed.)MAS'UD, Fuad. Essentials of English Grammar: A Practical Guide.--Ed.2. BPFE, 1992.
Atenció: Aquestes cites poden no estar 100% correctes.