@Article{AehligJohannsen02,
  author =       {Aehlig, Klaus and Johannsen, Jan},
  title =        {An Elementary Fragment of Second-Order Lambda Calculus},
  journal =      {ACM Transactions on Computational Logic},
  year =         2005,
  volume =       6,
  number =       2,
  month =        apr,
  pages =        {468--480}
}