Published in Nautilus, in 1999, in volume 113, pages 1-3

Published in Nautilus, in 1999, in volume 113, pages 4-42

Published in Nautilus, in 1999, in volume 113, pages 73-77

Published in Nautilus, in 1999, in volume 113, pages 78-101

Published in Nautilus, in 1999, in volume 113, pages 103-120

Published in Nautilus, in 1999, in volume 113, pages 121-126

Published in The Nautilus, in 1999, in volume 113, issue 4, pages 127-150