Gaya APA
Ritchie, J., I.Crouch, G. (2003).
The Competitive Destination A Sustainable Tourism Perspective .
london:
CAB internaional.
Gaya MLA
Ritchie, J.R.Brent., I.Crouch, Geoffrey.
"The Competitive Destination A Sustainable Tourism Perspective".
london:
CAB internaional,
2003.
BUKU.