Secondary research

Some secondary research links I've found:

[sorted by relevance]

http://www.epa.gov/climatechange/emissions/downloads/emissionsfactorsbrochure2004.pdf

http://geosci.uchicago.edu/~gidon/papers/nutri/nutriEI.pdf

http://www.leopold.iastate.edu/pubs/staff/files/fuel0608.pdf