@article{michail2013does,
  title = {Does Size Matter? Scaling of CO2 Emissions and U.S. Urban Areas}
  author = {Michail Fragkias, José Lobo, Deborah Strumsky, Karen C. Seto},
  journal = {PLOS ONE},
  doi = {10.1371/journal.pone.0064727},
  year = {2013}
}