References
1. Perlitz, L; 2008; SIRXSLS001A Sell products and services; Pearson Education
2. Buhalis, Dimitrios; 2003 (1st edition); eTourism: Information technology for strategic tourism management; Prentice Hall
3. Lennon, John; 2003 (1st edition); Tourism Statistics: International Perspectives and Current Issues, Cengage Learning EMEA
4. Rosen, K; 2007 (2nd edition); Closing the sale; Alpha Penguin