New parameterisation needed for the plant physiological responses to rising CO2; evidence from fossil leaves and tree ring 13C based water use efficiency records at Laanila and Kiruna. In: Young, G. & McCarroll, D. (eds.). European climate of the last millennium. Millennium milestone meeting 3, Calla Millor, Mallorca,

Gagen, M.; Finsinger, W.; McCarroll, D.; Wagner-Cremer, F.; Loader, N.; Robertson, I.; Jalkanen, R. (2009)