APA (7th ed.) Citation

Hornby, A. (1989). Oxford advanced learner's dictionary of current english (4th ed.). Oxford university press.

Chicago Style (17th ed.) Citation

Hornby, A. Oxford Advanced Learner's Dictionary of Current English. 4th ed. Oxford: Oxford university press, 1989.

MLA (9th ed.) Citation

Hornby, A. Oxford Advanced Learner's Dictionary of Current English. 4th ed. Oxford university press, 1989.