@misc{indiciae036615f0dbf6,
  title = {Upper limits on the isotropic gravitational radiation background from pulsar timing analysis},
  author = {Hellings, R. W. and Downs, G. S.},
  year = {1983},
  url = {https://ntrs.nasa.gov/citations/19830041859},
  note = {Source identifier: 19830041859}
}