Published in Nautilus, in 1972, in volume 85, pages 78-84

Published in Nautilus, in 1972, in volume 85, pages 96-100

Published in Nautilus, in 1972, in volume 85, pages 100-106

Published in Nautilus, in 1972, in volume 85, pages 120-125

Published in Nautilus, in 1972, in volume 85, pages 128-135

Published in Nautilus, in 1972, in volume 86, pages 1-2

Published in Nautilus, in 1972, in volume 86, pages 3-7

Published in Nautilus, in 1972, in volume 86, pages 16-17

Published in Nautilus, in 1972, in volume 86, pages 27-50

Published in Nautilus, in 1972, in volume 86, pages 51-52

Published in Nautilus, in 1972, in volume 86, pages 53-55

Published in Nautilus, in 1972, in volume 86, pages 56-59

Published in Nautilus, in 1972, in volume 86, pages 80

Published in Nautilus, in 1972, in volume 86, issue 2-4, pages 83-84