@misc{indiciaefec878c34139,
  title = {Nonlinear effects on sonic boom intensity},
  author = {Landahl, M. and Lofgren, P. and Ryhming, I.},
  year = {1971},
  url = {https://ntrs.nasa.gov/citations/19710018888},
  note = {Source identifier: 19710018888}
}