APA

(1989). Websters dictionary of English usage. : Merriam-Webster Incorporated, Massachusetts.

Chicago

1989. Websters dictionary of English usage. : Merriam-Webster Incorporated, Massachusetts.

Harvard

(1989). Websters dictionary of English usage. : Merriam-Webster Incorporated, Massachusetts.

MLA

Websters dictionary of English usage. : Merriam-Webster Incorporated, Massachusetts. 1989.