Coaches, please excuse this if it sounds like a sales pitch - I dont really know any other way to communicate this information.
The Shotgun and Modern Short Punt by Lou Howard is reportedly one of the most respected sources of information on the Single Wing and its derivatives.
It is available in download form at
http://www.compusportsmedia.com/main/ebook.asp?EbookID=10103
We also send out a paperback copy (new) automatically when the eBook is purchased and plan to do so until we run out.