Colony Collapse Disorder: Have We Seen This Before? by Robyn M. Underwood & Dennis vanEngelsdorp http://www.beeculture.com/content/ColonyCollapseDisorderPDFs/7%20Colony%20Collapse%20Disorder%20Have%20We%20Seen%20This%20Before%20-%20Robyn%20M.%20Underwood%20and%20Dennis%20vanEngelsdorp.pdf