@article{ Bak_Schmidt??,
  author = {Bak, M.J. and Schmidt, E.M.},
  title = {An Improved time-amplitude window discriminator},
  journal = {IEEE Trans. Biomed. Eng.},
  year = {???? year not known},
  volume = {24},
  pages = {486-489},
  en_number = { }
}