@misc{indiciaeee2db0849aa0,
  title = {A study of blade-vortex interaction sound generation and directionality},
  author = {Ringler, Todd D. and George, Albert R. and Steele, James B.},
  year = {1991},
  url = {https://ntrs.nasa.gov/citations/19930045405},
  note = {Source identifier: 19930045405}
}