I don’t have a link, but I work in the film/video industry, and we sometimes get requests to make the DVDs we produce “uncopyable” by our clients… until they hear how much it costs.
Basically, the way I understand it, one way that works half the time to make a DVD uncopyable is to add extra bits that don’t get played by your DVD player that, when ripped by a computer, cause errors, and then make the resulting VIDEO_TS folders unplayable and unburnable. They do this by making the ripping software think that there was an error, which there actually was, but it’s not in a part of the disc that is essential to the disc’s playback.
I don’t know if I explained that very well. I have a rather small grasp of it myself, but like I said, this method works sometimes, and sometimes it doesn’t.