​¹Brennan, Thomas. n. page. Web. 24 Nov. 2012. <http://www.photobiology.info/History_Timelines/Hist-Photosyn.html>.

²Arizona State University. "Scientists unlock mystery in important photosynthesis step." ScienceDaily, 20 Feb. 2010. Web. 25 Nov. 2012.

³n. page. Web. 26 Nov. 2012. <[http://www.franklin.k12.ma.us/hs/PS Discovery.pdf]>.

“Contribution to the History of Photosynthesis: Johann Baptista Van Helmont and John Woodward.” Crop Farming Review.2012. Web. 25 Nov. 2012. <http://www.cropsreview.com/van-helmont.html>

Xiong, Jin. Fischer, William M. Inoue, Kazuhito. Nakahara, Masaaki. Bauer, Carl E. . "Molecular evidence for the early evolution of photosynthesis." . . (2000): . Web. <http://www.ncbi.nlm.nih.gov/pubmed/10976061>

"leaf" Web. 24 Nov. 2012. <http://www.wired.com/images_blogs/wiredscience/2010/02/leafveins.jpg>

"photosynthesis" Web. 24 Nov. 2012. <http://www.cleanplantshappyplants.com/images/photosynthesis01.jpg.

"sprout" Web. 24 Nov. 2012. <http://www.jnsgrupo.com.br/images/home-01.jpg>

"aristotle" Web. 24 Nov. 2012 <http://web.uvic.ca/~lalonde/psyc335/notes/images/theorists/aristotle2.gif>

"jan baptista van helmont experiment" Web. 24 Nov.2012<http://wps.prenhall.com/wps/media/objects/488/500252/images/AACDCDD0.jpg>