I would assume you're talking about the sound deadener inside the door panels. We used to stock it at the dealer in a bulk roll, but I haven't seen it in many years. I've lined many a door with foam carpet padding. Cheap, and it seems to work as well as the factory stuff. As far as the brown paper, forget it. GM cars years ago had a problem with cold air leakage around the interior door handles. The recommended factory fix was to remove the door handle and tape a sheet of 4 or 6 mil plastic sheet over the entire door. Rivet the door handle right thru the plastic. Punch holes for the barbed door panel retainers, trim to fit the perimeter, and cut slots as small as possible for the pwr. window, pwr. lock harnesses, door latch rod and the mirror cable. Secure with strip caulk and duct tape. Every car of my own got this treatment when I had a door panel off. In addition to being truly waterproof rather than somewhat water resistant (brown paper), it seals the interior better and deters heat exchange with the exterior. A little more work, but worth it in the long run.
Bill