@misc{indiciaecf65654349e5,
  title = {Helicopter vibration reduction using structural optimization with aeroelastic/multidisciplinary constraints - A survey},
  author = {Friedmann, Peretz P.},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19910048904},
  note = {Source identifier: 19910048904}
}