@misc{indiciaec2770210f14c,
  title = {Flow interaction and noise from a counter rotating propeller},
  author = {Chung, Jin-Deog and Walls, James L. and Nagel, Robert T.},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19910034754},
  note = {Source identifier: 19910034754}
}