@misc{indiciae1e11845f08a9,
  title = {Solar flare activity - Evidence for large-scale changes in the past},
  author = {Zook, H. A. and Hartung, J. B. and Storzer, D.},
  year = {1977},
  url = {https://ntrs.nasa.gov/citations/19770063695},
  note = {Source identifier: 19770063695}
}