@article{weisz2006physical,
  title = {Physical and monetary input–output analysis: What makes the difference?}
  author = {Weisz, Helga; Duchin, Faye},
  journal = {Ecological Economics},
  url = {http://www.sciencedirect.com/science/article/pii/S092180090500248X},
  doi = {10.1016/j.ecolecon.2005.05.011},
  year = {2006}
}