@misc{indiciae8b75a090653e,
  title = {Approximate solution for streamlines about a lifting rotor having uniform loading and operating in hovering or low-speed vertical-ascent flight conditions},
  author = {Castles, Walter, Jr},
  year = {1957},
  url = {https://ntrs.nasa.gov/citations/19930084869},
  note = {Source identifier: 19930084869}
}