@misc{indiciae7ecf25088207,
  title = {Multifrequency observations},
  author = {Glitz, R. and Heel, F. and Kietzmann, H. and Oettl, H. and Schmullius, C.},
  year = {1993},
  url = {https://ntrs.nasa.gov/citations/19940011429},
  note = {Source identifier: 19940011429}
}