@misc{indiciae214c2e216b8b,
  title = {A thermosphere composition measurement using a quadrupole mass spectrometer with a side energy focussing quasi-open ion source},
  author = {Niemann, H. B. and Spencer, N. W. and Schmitt, G. A.},
  year = {1971},
  url = {https://ntrs.nasa.gov/citations/19720003678},
  note = {Source identifier: 19720003678}
}