Published in Nautilus, in 1987, in volume 101, pages 3-8

Published in Nautilus, in 1987, in volume 101, pages 59-68

Published in Nautilus, in 1987, in volume 101, pages 111-116

Published in Nautilus, in 1987, in volume 101, pages 133-139

Published in Nautilus, in 1987, in volume 101, pages 154

Published in Nautilus, in 1987, in volume 101, pages 155-161

Published in Nautilus, in 1987, in volume 101, pages 162-165

Published in Nautilus, in 1987, in volume 101, pages 166-181

Published in Nautilus, in 1987, in volume 101, pages 200-206