Coal and Petroleum

• Fossil fuels
  
• Coal
  
• Fossil fuel, by Wikipedia
  
• Encarta's page on fossil fuels
  
• Fossil fuel, by the Free Dictionary
  
• Encarta's page on carbon
  
• Coal
  
• The carbon cycle
  
• Petroleum (Oil) - A Fossil Fuel
  
• Coal: - A Fossil Fuel