@Book{389340080X,
  author = {Russell, Bertrand},
  title  = {Philosophie des Abendlandes},

  year   = {2007},
  number = {},
  url    = {http://www.amazon.de/gp/redirect.html%3FASIN=389340080X%26tag=ws%26lcode=xm2%26cID=2025%26ccmID=165953%26location=/o/ASIN/389340080X%253FSubscriptionId=13CT5CVB80YFWJEPWS02},

  const  = {\ text}
}
@Book{lem2003sterntagebuecher,
  author = {Lem, Stanislaw},
  title  = {Sterntagebücher},

  year   = {2003},
  number = {},
  url    = {http://www.amazon.de/exec/obidos/ASIN/3518455346/},

  const  = {\ text}
}