@article{456506,
      url = {http://digitallibrary.un.org/record/456506},
      title = {Development of international classes within categories /},
      publisher = {UN,},
      recid = {456506},
      pages = {4 p.},
      address = {Geneva :. 2001-12-21},
      year = {2001},
      month = {Dec},
}