@misc{indiciae654e1bb8a3f5,
  title = {Free-piston Stirling engine conceptual design and technologies for space power, phase 1},
  author = {Penswick, L. Barry and Beale, William T. and Wood, J. Gary},
  year = {1990},
  url = {https://ntrs.nasa.gov/citations/19920022001},
  note = {Source identifier: 19920022001}
}