1. Amazon Web Site, http://www.amazon.com .
2. Ankolekar, A., Burstein, M., Hobbs, J.R., Lassila, O., Martin, D.L., McIlraith, S.A., Narayanan, S., Paolucci, M., Payne, T.R., Sycara, K., Zeng, H.: DAML-S: Semantic Markup for Web Services. In: International Semantic Web Workshop (2001).
3. Berners-Lee, T., Hendler, J., Fensel, D.: The Semantic Web. In: Scientific American 78(3) (2001): 20–88.
4. Christensen, E., Curbera, F., Meredith, G., Weerawarana, S.: Web Services Description Language (WSDL) 1.1. http://www.w3.org/TR/2001/NOTE-wsdl-20010315 (2001).
5. CIA Factbook Web Site, http://www.cia.gov/cia/publications/factbook (2001).