Leading Hotels of the World, 2000
Buku Teks
Smithies, Michael
Oxford University Press, 1986
Buku Teks
Kaufman, David, author
Labensart Media, 2000
Buku Referensi
New York, 2006
Buku Teks
Dalton, Bill, author
California Moon Publications , 1991
Buku Referensi