Commercial and economic literature on patent term extension

While there is quite a lot of accessible literature on the legal requirements that govern the extension of the duration of the patent monopoly, I've had less luck finding current and readable material on the commercial and economic impact of patent term extension, whether in Europe's SPC zone or outside it.

In order to build up a useful reading list, I am again asking readers of this blog if they can make any recommendations -- whether articles, chapters of books, websites or anything else. All recommendations will of course be shared with readers of The SPC Blog. Please email The SPC Blog here.