Augustine, D.J., Dijkstra, F.A., Hamilton III, E.W. and Morgan, J.A. 2011. Rhizosphere interactions, carbon allocation, and nitrogen acquisition of two perennial North American grasses in response to defoliation and elevated atmospheric CO2. Oecologia 165: 755-770.

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.

LeCain, D.R., Morgan, J.A., Mosier, A.R. and Nelson, J.A. 2003. Soil and plant water relations determine photosynthetic responses of C3 and C4 grasses in a semi-arid ecosystem under elevated CO2. Annals of Botany 92: 41-52.

Morgan, J.A., LeCain, D.R., Read, J.J., Hunt, H.W. and Knight, W.G. 1998. Photosynthetic pathway and ontogeny affect water relations and the impact of CO2 on Bouteloua gracilis (C4) and Pascopyrum smithii (C3). Oecologia 114: 483-493.