Gaya APA

Vallen, G, K., Vallen, J, J. (2005). CHECK-IN CHECK-OUT MANAGING HOTEL OPERATIONS Seventh Edition (7). New Jersey: Prentice-Hall.

Gaya MLA

Vallen, Gary, K.., Vallen, Jerome, J.. "CHECK-IN CHECK-OUT MANAGING HOTEL OPERATIONS Seventh Edition". 7 New Jersey: Prentice-Hall, 2005. Text.