Published in Nautilus, in 1981, in volume 95, pages 72-77

Published in Nautilus, in 1981, in volume 95, pages 77-82

Published in Nautilus, in 1981, in volume 95, pages 96-99

Published in Nautilus, in 1981, in volume 95, pages 101-105

Published in Nautilus, in 1981, in volume 95, pages 116-124

Published in Nautilus, in 1981, in volume 95, pages 150-156

Published in Nautilus, in 1981, in volume 95, issue 4, pages 169-170

Published in Nautilus, in 1981, in volume 95, issue 4, pages 171-177

Published in Nautilus, in 1981, in volume 95, issue 4, pages 178-179

Published in Nautilus, in 1981, in volume 95, issue 4, pages 186-188

Published in Nautilus, in 1981, in volume 95, issue 4, pages 189-193