APA (7e ed.) Bronvermelding

Callis, S. (1994). Effective writing for business. Buckingham Tutors Pub.

Chicago (17e ed.) Bronvermelding

Callis, Sidney. Effective Writing for Business. Buckingham, Bucks, U.K: Buckingham Tutors Pub, 1994.

MLA (9e ed.) Bronvermelding

Callis, Sidney. Effective Writing for Business. Buckingham Tutors Pub, 1994.

Let op: Deze citaties zijn niet altijd 100% accuraat.