http://www.space.com/15589-galileo-galilei.html
http://www.infoplease.com/encyclopedia/people/galileo-contributions-to-astronomy.html
http://planetfacts.org/orbit-and-rotation-of-earth/
http://abyss.uoregon.edu/~js/glossary/galileo.html
http://www.nrdc.org/globalwarming/
http://www.livescience.com/37003-global-warming.html
http://www.biography.com/people/nicolaus-copernicus-9256984
http://copernicus.torun.pl/en/biography/1473-1543/3
http://www.thefamouspeople.com/profiles/nicolaus-copernicus-5024.php
http://blogs.yis.ac.jp/14shimomuram/nicolaus-copernicus/nicolaus-copernicus-his-findings-contribution-contribution/
http://www.nrdc.org/globalwarming/fcons.asp
http://www.theatlantic.com/magazine/archive/2007/04/global-warming-who-loses-and-who-wins/305698/
http://www.infoplease.com/encyclopedia/people/galileo-contributions-to-astronomy.html
http://planetfacts.org/orbit-and-rotation-of-earth/
http://abyss.uoregon.edu/~js/glossary/galileo.html
http://www.nrdc.org/globalwarming/
http://www.livescience.com/37003-global-warming.html
http://www.biography.com/people/nicolaus-copernicus-9256984
http://copernicus.torun.pl/en/biography/1473-1543/3
http://www.thefamouspeople.com/profiles/nicolaus-copernicus-5024.php
http://blogs.yis.ac.jp/14shimomuram/nicolaus-copernicus/nicolaus-copernicus-his-findings-contribution-contribution/
http://www.nrdc.org/globalwarming/fcons.asp
http://www.theatlantic.com/magazine/archive/2007/04/global-warming-who-loses-and-who-wins/305698/