@article{wiedmann2015the,
  title = {The material footprint of nations}
  author = {Wiedmann, Thomas O.; Schandl, Heinz; Lenzen, Manfred; Moran, Daniel; Suh, Sangwon; West, James; Kanemoto, Keiichiro},
  journal = {PNAS},
  url = {https://www.pnas.org/content/112/20/6271},
  doi = {10.1073/pnas.1220362110},
  year = {2015}
}