@misc{indiciae4ac0c028ca53,
  title = {JT9D-7A (SP) jet engine performance deterioration trends},
  author = {Richter, G. P. and Olsson, W. J. and Andersen, N. B.},
  year = {1980},
  url = {https://ntrs.nasa.gov/citations/19800011791},
  note = {Source identifier: 19800011791}
}