Hattenschwiler, S.  2001.  Tree seedling growth in natural deep shade: functional traits related to interspecific variation in response to elevated CO2.  Oecologia 129: 31-42.

Hattenschwiler, S. and Korner, C.  2000.  Tree seedling responses to in situ CO2-enrichment differ among species and depend on understory light availability.  Global Change Biology 6: 213-226.

Heath, J., Ayres, E., Possell, M., Bardgett, R.D., Black, H.I.J., Grant, H., Ineson, P. and Kerstiens, G.  2005.  Rising atmospheric CO2 reduces sequestration of root-derived soil carbon.  Science 309: 1711-1713.