A matter of divergence: Tracking recent warming at hemispheric scales using tree ring data, Wilson, R.; D'Arrigo, R.; Buckley, B.; Buntgen, U.; Esper, J.; Frank, D.; Luckman, B.; Payette, S.; Vose, R.; Youngblut, D. , Journal of Geophysical Research-Atmospheres, Sep 11, Volume 112, Issue D17, p.-, (2007), Doi 10.1029/2006jd008318 Abstract