che, there is a paper posted somewhere within the forum from a Pennsylvanian college and also try this link from NCSU:
http://www.bae.ncsu.edu/people/faculty/sherman/index.html
I found the Pennsylvania paper;
http://www.wormdigest.org/component/option,com_joomlaboard/Itemid,50/func,view/id,409/catid,6/