@misc{indiciae9a1dd236c09d,
  title = {Ultrasonic/Sonic Rotary-Hammer Drills},
  author = {Badescu, Mircea and Sherrit, Stewart and Bar-Cohen, Yoseph and Bao, Xiaoqi and Kassab, Steve},
  year = {2010},
  url = {https://ntrs.nasa.gov/citations/20100024421},
  note = {Source identifier: 20100024421}
}