@misc{indiciaec8ecc8aae334,
  title = {Ultrasonic/Sonic Jackhammer},
  author = {Bar-Cohen, Yoseph and Sherrit, Stewart and Herz, Jack L.},
  year = {2014},
  url = {https://ntrs.nasa.gov/citations/20150003394},
  note = {Source identifier: 20150003394}
}