@misc{indiciae04f216412fa5,
  title = {Differential spot-size focus servo},
  author = {Milster, T. D. and Wang, M. S. and Froehlich, F. F. and Kann, J. L. and Treptau, J. P. and Erwin, K. E.},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19920005691},
  note = {Source identifier: 19920005691}
}