Παραπομπή σε μορφή APA (7η εκδ.)

Howell, D. W. (1993). Passport: An introduction to the travel and tourism industry (2nd ed.). South-Western Pub.

Παραπομπή σε μορφή Chicago (17η εκδ.)

Howell, David W. Passport: An Introduction to the Travel and Tourism Industry. 2nd ed. Cincinnati, Ohio: South-Western Pub, 1993.

Παραπομπή σε μορφή MLA (9th εκδ.)

Howell, David W. Passport: An Introduction to the Travel and Tourism Industry. 2nd ed. South-Western Pub, 1993.