1.
http://www.atmosphere.mpg.de/enid/Nr_8_April_2__6_Ozone___N2_cycle/C__The_nitrogen_cycle_5lp.html
Access date: 24/11/2011
Author: Elmar Uherek - Max Planck Institute for Chemistry, Mainz
2.
http://en.wikipedia.org/wiki/Nitrogen_cycle
Access date: 16/11/2011
Author: Wikipedia
3.
http://www.ehow.com/video_4801947_nitrogen-cycle_.html
Access date: 30/11/2011
Author: Unknown
4.
http://www.dnatube.com/video/4223/The-Nitrogen-Fixation-Cycle-Presented-by-Dr-Undergrad
Access date: 30/11/2011
Author: Unknown
5.
Access date: 28/11/2011
Author: National Science Foundation
Book/s:
1.
Title: Science Dimensions 3
Author/s: Greg Rickard, Geoff Phillips, Janette Ellis, Karin Johnstones, Faye Jeffery, Peter Jeans & Peter Roberson
Date access: 16/11/2011
