Kgope, B.S., Bond, W.J. and Midgley, G.F. 2010. Growth responses of African savanna trees implicate atmospheric [CO2] as a driver of past and current changes in savanna tree cover. Austral Ecology 35: 451-463.

Khurana, E. and Singh, J.S. 2004. Response of five dry tropical tree seedlings to elevated CO2: Impact of seed size and successional status. New Forests 27: 139-157.