An improved device for making harmonic prints from radiographs of great contrast.

@article{Spiegler1953AnID,
  title={An improved device for making harmonic prints from radiographs of great contrast.},
  author={G Spiegler and P GILES},
  journal={The British journal of radiology},
  year={1953},
  volume={26 303},
  pages={130-5}
}