@misc{indiciaec980913b309d,
  title = {Ultrasonic/Sonic Jackhammer},
  author = {Bar-Cohen, Yoseph and Sherrit, Stewart and Herz, Jack},
  year = {2005},
  url = {https://ntrs.nasa.gov/citations/20110014887},
  note = {Source identifier: 20110014887}
}