@misc{indiciaec238cef3eca7,
  title = {Penetrator Coring Apparatus for Cometary Surfaces},
  author = {Braun, David F. and Heinrich, Michael and Ai, Huirong Anita and Ahrens, Thomas J.},
  year = {2004},
  url = {https://ntrs.nasa.gov/citations/20040062104},
  note = {Source identifier: 20040062104}
}