Gaya APA
Goeldner, C, R., Ritchie, J, B. (2009).
Tourism Principles, Practice, Philosophies (11th Ed.).
New Jersey:
John Wiley & Sons, Inc..
Gaya MLA
Goeldner, Charles, R.., Ritchie, J.R., Brent.
"Tourism Principles, Practice, Philosophies".
11th Ed.
New Jersey:
John Wiley & Sons, Inc.,
2009.
BUKU.