%0 Journal Article %T Elevated CO 2 concentrations and stomatal density: observations from 17 plant species growing in a CO 2 spring in central Italy %A Bettarini, Isabella %A Vaccari, Francesco P. %A Miglietta, Franco %J Global Change Biology %V 4 %N 1 %@ 1354-1013 %D 1998-01-01 %I Wiley Subscription Services, Inc., A Wiley Company %~ DeepDyve