@article{361746,
      url = {http://digitallibrary.un.org/record/361746},
      title = {Linear duration invariants},
      publisher = {UN University :},
      recid = {361746},
      pages = {i, 29 p.},
      address = {Tokyo :. 1993-07},
      year = {1993},
      month = {Jul},
}