@article{Ritz2000,
  author    = {Ritz, Thomas},
  title     = {Personalized information services : an electronic information commodity and its production},
  series = {International Journal of E-Business Strategy Management},
  volume    = {2},
  journal   = {International Journal of E-Business Strategy Management},
  number    = {2},
  issn      = {1467-0305},
  year      = {2000},
  language  = {en}
}
@article{Ritz2000,
  author    = {Ritz, Thomas},
  title     = {Information Channels},
  series = {Information Technology. Nr. 52 (2000), H. 08. Mai 2000},
  journal   = {Information Technology. Nr. 52 (2000), H. 08. Mai 2000},
  pages     = {15 -- 15},
  year      = {2000},
  language  = {en}
}