The Dow Jones industrial average passed the 10,000 mark twice this week, opened this morning just a few points shy of the milestone, and will, in all probability, finish the day in record territory. While the breakthrough to 10,000 has no significance in and of itself for the market, it is a symbol of the strong optimism over America's improbably steady growth in the face of economic reversals all over the world. The sites listed provide information about this historical financial feat.