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