@misc{indiciae9b31c3c27b3c,
  title = {On the Relation Between Spotless Days and the Sunspot Cycle},
  author = {Wilson, Robert M. and Hathaway, David H.},
  year = {2005},
  url = {https://ntrs.nasa.gov/citations/20050165094},
  note = {Source identifier: 20050165094}
}