@misc{indiciaecc40bcda560f,
  title = {A simple method for designing structural models with closely spaced modes of vibration},
  author = {Hallauer, W. L., Jr. and Weisshaar, T. A. and Shostak, A. G.},
  year = {1978},
  url = {https://ntrs.nasa.gov/citations/19790036490},
  note = {Source identifier: 19790036490}
}