@article{257257,
      url = {http://digitallibrary.un.org/record/257257},
      title = {Satellite navigation and location systems : background  paper 4},
      publisher = {UN,},
      recid = {257257},
      pages = {19 p.},
      address = {[Vienna] :. 1998-05-27},
      year = {1998},
      month = {May},
}