Hass, L., Hamel, M., Sabo, A., & Tall, C. (2008). Wisconsin climate change activity guide: http://dnr.wi.gov/org/caer/ce/eek/teacher/Climateguide/PDF/WisCCGuideALL.pdf retrieved January 17, 2013.

IPCC, 2007: Climate Change 2007: The Physical Science Basis. Contribution of Working Group I to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change [Solomon, S., D. Qin, M. Manning (eds.)].

Michigan High School Science Content Expectations Companion Document. http://www.michigan.gov/documents/mde/ESClarification1_211293_7.pdf

NASA. Carbon Cycle. Retrieved January 17, 2013, from http://earthobservatory.nasa.gov/Features/CarbonCycle/page2.php

NOAA. Carbon Cycle Science. Retrieved January 17, 2013, from http://www.esrl.noaa.gov/research/themes/carbon/