@article{100933,
      url = {http://digitallibrary.un.org/record/100933},
      title = {Preparation of an industrial classification of medium-rank  coals : replies to the questionnaire /},
      publisher = {UN,},
      recid = {100933},
      pages = {5 p.},
      address = {Geneva :. 1982-07-12},
      year = {1982},
      month = {Jul},
}