Barrett, D.J. and Gifford, R.M.  1999.  Increased C-gain by an endemic Australian pasture grass at elevated atmospheric CO2 concentration when supplied with non-liable inorganic phosphorus.  Australian Journal of Plant Physiology 26: 443-451.

Navas, M.-L., Garnier, E., Austin, M.P. and Gifford, R.M.  1999.  Effect of competition on the responses of grasses and legumes to elevated atmospheric CO2 along a nitrogen gradient: differeences between isolated plants, monocultures and multi-species mixtures.  New Phytologist 143: 323-331.