Reich, P.B., Tilman, D., Craine, J., Ellsworth, D., Tjoelker, M.G., Knops, J., Wedin, D., Naeem, S., Bahauddin, D., Goth, J., Bengtson, W. and Lee, T.D.  2001.  Do species and functional groups differ in acquisition and use of C, N and water under varying atmospheric CO2 and N availability regimes?  A field test with 16 grassland species.  New Phytologist 150: 435-448.

West, J.B., HilleRisLambers, J., Lee, T.D., Hobbie, S.E. and Reich, P.B.  2005.  Legume species identity and soil nitrogen supply determine symbiotic nitrogen-fixation responses to elevated atmospheric [CO2].  New Phytologist 167: 523-530.