Most of them should be hot-linked. Click on the words of a different color in the relevant sentences. Some may have been unlinked by the editors. I wrote this a long time ago and editors have since changed it many times. It used to have a list of source and resource links at the bottom, but the editors removed them long ago and insisted on in-text links. It seems to lose links (and photos) every time the staff editors change it. I've even seen them add links that were later removed by a different editor. I haven't made any repairs lately because it's an almost ten-year-old article that only gets maybe a few hundred views a day, tops. The original links were most likely removed due to being dead links.