Published in Nautilus, in 1962, in volume 75, pages 102-107
Published in Nautilus, in 1962, in volume 76, pages 1-7
Published in Nautilus, in 1962, in volume 76, pages 39-44
Published in Nautilus, in 1962, in volume 76, pages 23-25
Published in Nautilus, in 1962, in volume 75, pages 116-121
Published in Nautilus, in 1962, in volume 76, pages 16-22