* [http://environment.nationalgeographic.com/environment/energy/great-energy-challenge/global-personal-energy-meter/?utm_source=NatGeocom&utm_medium=Email&utm_content=multi_20130218&utm_campaign=MultiProduct Cálculo de la huella de carbono personal] en National Geographic.* [http://www.footprintnetwork.org/es/index.php/GFN/page/personal_footprint/ Cálculo de la huella ecológica personal]en Global Footprint Network.