@article{93862,
      note = {Includes list of references.},
      url = {http://digitallibrary.un.org/record/93862},
      title = {ECE Standard Statistical Classification of Ambient Air  Quality : paper /},
      publisher = {UN,},
      recid = {93862},
      pages = {36 p. :},
      address = {Geneva :. 1990-03-29},
      year = {1990},
      month = {Mar},
}