Dhillion, S.S., Roy, J. and Abrams, M.  1996.  Assessing the impact of elevated CO2 on soil microbial activity in a Mediterranean model ecosystem.  Plant and Soil 187: 333-342.

Roumet, C., Garnier, E., Suzor, H., Salager, J.-L. and Roy, J.  2000.  Short and long-term responses of whole-plant gas exchange to elevated CO2 in four herbaceous species.  Environmental and Experimental Botany 43: 155-169.