@article{Hayakawa:2023xM,
  author = "Hayakawa, Hisashi",
  title = "{Digitizations of Historical Solar Cosmic-Ray Measurements for the GLE 1 – 4}",
  doi = "10.22323/1.444.1328",
  journal = "PoS",
  year = 2023,
  volume = "ICRC2023",
  pages = "1328"
}