@misc{indiciaeb07e184a49d9,
  title = {Large diffraction gratings ruled on a commercial measuring machine controlled interferometrically},
  author = {Harrison, G. R. and Thompson, S. W.},
  year = {1970},
  url = {https://ntrs.nasa.gov/citations/19700053705},
  note = {Source identifier: 19700053705}
}