Cita APA (7th ed.)

Allen, W. (1959). Living English Structure- Key to the exercise (14th.). Orient Longman.

Cita Chicago (17th ed.)

Allen, W. Living English Structure- Key to the Exercise. 14th. Hyderabad: Orient Longman, 1959.

Cita MLA (9th ed.)

Allen, W. Living English Structure- Key to the Exercise. 14th. Orient Longman, 1959.