References

Ivers, K.S., & Barron, A.E. (2006). Multimedia projects in education, designing, producing and assessing. Westport, CT: Libraries Unlimited.

Rubistar. (2008). Retrieved from http://rubistar.4teachers.org/

Reference Picture © 2009-2010 St Joseph County Public Library, South Bend, Indiana

Wikipedia.—http://en.wikipedia.org/wiki/Ecosystem

1 ^{a b c d} ”Biology Concepts & Connections Sixth Edition”, Campbell, Neil A. (2009), page 2, 3 and G-9. Retrieved 2010-06-14.

2^ (1996) Geosystems: An Introduction to Physical Geography. Prentice Hall Inc.