@article{Adey2005,
  author    = {Philip Adey},
  title     = {Cognitive acceleration},
  journal   = {LLF-Berichte / Universit{\"a}t Potsdam, Zentrum f{\"u}r Lehrerbildung},
  series    = {science and other entrances to formal operations},
  volume    = {7},
  year      = {2005},
}