Adam, N.R., Owensby, C.E. and Ham, J.M. 2000. The effect of CO2 enrichment on leaf photosynthetic rates and instantaneous water use efficiency of Andropogon gerardii in the tallgrass prairie. Photosynthesis Research 65: 121-129.

Hamerlynck, E.P., McAllister, C.A., Knapp, A.K., Ham, J.M. and Owensby, C.E. 1997. Photosynthetic gas exchange and water relation responses of three tallgrass prairie species to elevated carbon dioxide and moderate drought. International Journal of Plant Science 158: 608-616.

Kakani, V.G., Surabhi, G.K. and Reddy, K.R. 2008. Photosynthesis and fluorescence respnses of C4 plant Andropogon gerardii acclimated to temperature and carbon dioxide. Photosynthetica 46: 420-430.

Kirkham, M.B., He, H., Bolger, T.P., Lawlor, D.J. and Kanemasu, E.T. 1991. Leaf photosynthesis and water use of big bluestem under elevated carbon dioxide. Crop Science 31: 1589-1594.

Knapp, A.K., Hamerlynck, E.P., and Owensby, C.E. 1993. Photosynthetic and water relations responses to elevated CO2 in the C4 grass Andropogon gerardii. International Journal of Plant Sciences 154: 459-466.

LeCain, D.R. and Morgan, J.A. 1998. Growth, gas exchange, leaf nitrogen and carbohydrate concentrations in NAD-ME and NADP-ME C4 grasses grown in elevated CO2. Physiologia Plantarum 102: 297-306.

Lee, T.D., Barrott, S.H. and Reich, P.B. 2011. Photosynthetic responses of 13 grassland species across 11 years of free-air CO2 enrichment is modest, consistent and independent of N supply. Global Change Biology 17: 2893-2904.

Stamenkovic, J. and Gustin, M.S. 2009. Nonstomatal versus stomatal uptake of atmospheric mercury. Environmental Science and Technology 43: 1367-1372.