United Nations, Department of Economic and Social Affairs, Population Division (2014)
Population Reference Bureau (2014)
Organization of the Petroleum Exporting Countries (OPEC) - (2013)
U.S. Energy Information Administration (EIA) - (2013)
International Energy Agency (IEA) and BP Statistical Review of World Energy (2013)
U.S. Energy Information Administration (EIA) - (2012)
British Geological Survey; Natural Environment Research Council (2010)
Organisation for Economic Co-operation and Development (OECD) - (2014)
World Wide Fund for Nature (WWF) -(2014)
Water.org (2014)
US International Developments and Statistics (2011); Statistic brain (2014); United Nations, Department of Economic and Social Affairs, Population Division (2014)
National Oceanic and Atmospheric Administration (NOAA) - (2014)
International Food Policy Research Institute (2014)
Food and Agriculture Organization of the United Nations - Statistics Division (FAOSTAT) - (2013)
Fontes para os dados de Portugal
PORDATA/INE (2013)
U.S. Energy Information Administration (EIA) - (2013)
U.S. Energy Information Administration (EIA) - (2012)
British Geological Survey; Natural Environment Research Council (2010)
Instituto Nacional de Estatística (INE) - (2012)
World Wide Fund for Nature (WWF) - (2014)
US International Developments and Statistics (2011); Statistic brain (2014); United Nations, Department of Economic and Social Affairs, Population Division (2014)
Food and Agriculture Organization of the United Nations - Statistics Division (FAOSTAT) - (2013)
