Cita APA (7a ed.)

Bywater, F. (1990). A Proficiency Course in English with Key (1se ed., 18th reprinting.). Nelson.

Cita Chicago Style (17a ed.)

Bywater, F.V. A Proficiency Course in English with Key. 1se ed., 18th reprinting. Walton-on-Thames: Nelson, 1990.

Cita MLA (9a ed.)

Bywater, F.V. A Proficiency Course in English with Key. 1se ed., 18th reprinting. Nelson, 1990.