@article{Liedtke1993,
  author    = {Liedtke, Christa},
  title     = {Material intensity of paper and board production in Western Europe},
  journal   = {Fresenius environmental bulletin},
  volume    = {2},
  number    = {8},
  pages     = {461 -- 466},
  year      = {1993},
  language  = {en}
}