@Article{bastide02unalogorithme,
  author = {Bastide, Y. and Taouil, R. and Pasquier, N. and Stumme, G. and Lakhal, L.},
  title  = {Pascal: un alogorithme d'extraction des motifs fréquents},
  journal = {Technique et Science Informatiques (TSI)},
  year   = {2002},
  number = {1},
  url    = {http://www.kde.cs.uni-kassel.de/stumme/papers/2001/TSI01.pdf},

  const  = {\ text}
}
@Book{Biethahn.2002,
  author = {Biethahn, J\"org and Tietze, Martin},
  title  = {Einf\"uhrung in die EDV f\"ur Wirtschaftswissenschaftler},

  year   = {2002},
  number = {},
  url    = {\url{http://www.gbv.de/dms/hebis-mainz/toc/104999128.pdf}},

  const  = {\ text}
}