Here’s a terrific lecture from Dr. Sommers based on the publication of the updated and expanded edition of his book, Richmond Redeemed. This is the standard history of one part of the Petersburg Siege. The lecture was delivered at the US Army Heritage and Education Center in Carlisle, PA in October of 2014 [Yes, that’s yours truly over there on the right]. It’s part of their “Perspectives in Military History” lecture series.
You can see C-SPAN’s coverage, with some different camera angles, here.