Style de citation APA (7e éd.)

Butterfiel, W. (1964). Effective personal letters (2nd rev.). Prentice Hall.

Style de citation Chicago (17e éd.)

Butterfiel, W. Effective Personal Letters. 2nd rev. Englewood Cliffs: Prentice Hall, 1964.

Style de citation MLA (9e éd.)

Butterfiel, W. Effective Personal Letters. 2nd rev. Prentice Hall, 1964.