@congreso_internacional{535,
  author = {Luis Martínez and Francisco Mata and E. Bernal},
  title = {Vertical Portals as paradigm of the e-commerce in the tourist companies},
  year = {2003},
  month = {May 7-9th},
  publisher = {II Congreso Internacional de la Sociedad de la Información y del Conocimiento},
  address = {, Madrid (Spain)},
}