@misc{indiciaec18b52affcf9,
  title = {The properties of X-ray selected BL Lac objects},
  author = {Maccacaro, T. and Gioia, I. M. and Maccagni, D. and Stocke, J. T.},
  year = {1986},
  url = {https://ntrs.nasa.gov/citations/19870026014},
  note = {Source identifier: 19870026014}
}