@HarryGindi Harry -- though I gather that Denis has given you Clark's thesis by now, it is worth pointing out that most universities subscribe to ProQuest, and on that website you can download most PhD theses that are not too old (certainly almost everything post 2000 in the US is available). Here's a link to Clark's thesis, which I just downloaded:
drive.google.com/file/d/1ABAFll1bvuAonCo6M1bUs42-R0xBI3TH/…