http://www.shodor.org/mvhs/carbon.html

http://www.carleton.edu/departments/GEOL/DaveSTELLA/Carbon/c_cycle_models.htm

http://www.whrc.org/carbon/index.htm

http://cdiac.ornl.gov/trends/emis/em_cont.htm

http://cdiac.ornl.gov/by_new/bysubjec.html#carbon

http://science.hq.nasa.gov/oceans/system/carbon.html

http://www.uky.edu/KGS/education/carbon_cycle.htm

http://www.grida.no/climate/vital/06.htm

http://www.grida.no/climate/vital/intro.htm