@article{kral2014the,
  title = {The Copper Balance of Cities}
  author = {Kral, Ulrich and Lin, Chih-Yi and Kellner, Katharina and Ma, Hwong-wen and Brunner, Paul H.},
  journal = {Journal of Industrial Ecology},
  doi = {10.1111/jiec.12088},
  year = {2014}
}