@article{PauliLutzenbergerRauetal.1994,
  author    = {Paul Pauli and W. Lutzenberger and H. Rau and N. Birbaumer and T. C. Rickard and R. A. Yaroush and L. E. J. Bourne},
  title     = {Brain potentials during mental arithmetic: effects of extensive practice and problem difficulty},
  year      = {1994},
}