@misc{indiciae814ce0306e3b,
  title = {Elasto-plastic impact of hemispherical shell impacting on hard rigid sphere},
  author = {Raftopoulos, D. D. and Spicer, A. L.},
  year = {1976},
  url = {https://ntrs.nasa.gov/citations/19770003341},
  note = {Source identifier: 19770003341}
}