@misc{indiciaecc65e2147d7c,
  title = {Ultra-high energy gamma rays},
  author = {Strong, A. W. and Wdowczyk, J. and Wolfendale, A. W.},
  year = {1973},
  url = {https://ntrs.nasa.gov/citations/19740006375},
  note = {Source identifier: 19740006375}
}