@book{SchroederBoedekerEdelstein2000,
  author    = {Schr{\"o}der, Eberhard and B{\"o}deker, Katja and Edelstein, Wolfgang},
  title     = {Proportional, combinatorial, and correlational reasoning : a manual including measurement procedures and descriptive analyses},
  series = {Materialien aus der Bildungsforschung},
  volume    = {70},
  journal   = {Materialien aus der Bildungsforschung},
  publisher = {Max-Planck-Inst. f{\"u}r Bildungsforschung},
  address   = {Berlin},
  isbn      = {3-87985-082-8},
  pages     = {173 S.},
  year      = {2000},
  language  = {en}
}
@book{SchroederBoedekerEdelstein2000,
  author    = {Schr{\"o}der, Eberhard and B{\"o}deker, Katja and Edelstein, Wolfgang},
  title     = {The development of syllogistic reasoning : a manual including measurement procedures and descriptive analyses},
  series = {Materialien aus der Bildungsforschung},
  volume    = {69},
  journal   = {Materialien aus der Bildungsforschung},
  publisher = {Max-Planck-Inst. f{\"u}r Bildungsforschung},
  address   = {Berlin},
  isbn      = {3-87985-081-X},
  pages     = {118 S.},
  year      = {2000},
  language  = {en}
}
@book{SchroederBoedekerEdelstein2000,
  author    = {Schr{\"o}der, Eberhard and B{\"o}deker, Katja and Edelstein, Wolfgang},
  title     = {The development of concrete thought : a manual including measurement procedures and descriptive analyses},
  series = {Materialien aus der Bildungsforschung},
  volume    = {67},
  journal   = {Materialien aus der Bildungsforschung},
  publisher = {Max-Planck-Inst. f{\"u}r Bildungsforschung},
  address   = {Berlin},
  isbn      = {3-87985-079-8},
  pages     = {95 S.},
  year      = {2000},
  language  = {en}
}
@book{SchroederBoedekerEdelstein2000,
  author    = {Schr{\"o}der, Eberhard and B{\"o}deker, Katja and Edelstein, Wolfgang},
  title     = {The development of formal thought : a manual including measurement procedures and descriptive analyses},
  series = {Materialien aus der Bildungsforschung},
  volume    = {68},
  journal   = {Materialien aus der Bildungsforschung},
  publisher = {Max-Planck-Inst. f{\"u}r Bildungsforschung},
  address   = {Berlin},
  isbn      = {3-87985-080-1},
  pages     = {252 S.},
  year      = {2000},
  language  = {en}
}