1. “Money and little red books”: Romanticism, tourism, and the rise of the guidebook;Allen;Literature Interpretation Theory,1996
2. Amazon France. (2010). Switzerland—Bestsellers. Retrieved 9 April, 2010, from.
3. Amazon Germany. (2010). Switzerland—Bestsellers. Retrieved 9 April, 2010, from .
4. Amazon UK. (2010). Switzerland—Bestsellers. Retrieved 9 April, 2010, from .
5. The practice of social research;Babbie,2001