@misc{indiciae84c26ab40fa1,
  title = {Controlling the Focus in Electron-Beam Welders},
  author = {Macfarlane, D. I. and Spiegel, K. W.},
  year = {1984},
  url = {https://ntrs.nasa.gov/citations/19830000664},
  note = {Source identifier: 19830000664}
}