@misc{brussels2017state,
  title = {State of the environment Report 2011-2014 Environment for a sustainable city Focus: urban metabolism, a balance of materials and energy flows}
  author = {Brussels Environment},
  url = {https://www.environment.brussels/state-environment/report-2011-2014/environnement-pour-une-ville-durable/focus-metabolisme-urbain},
  year = {2017}
}