@misc{indiciaeabeb612db8c6,
  title = {Vacuum pumping system for spaceborne passive hydrogen masers},
  author = {Wolf, S. A. and Gubser, D. U. and Jones, L. D.},
  year = {1981},
  url = {https://ntrs.nasa.gov/citations/19810018955},
  note = {Source identifier: 19810018955}
}