7 citations as recorded by crossref.

1. The Great Storm of May 1921: An Exemplar of a Dangerous Space Weather Event M. Hapgood https://doi.org/10.1029/2019SW002195
2. Flare-productive active regions S. Toriumi & H. Wang https://doi.org/10.1007/s41116-019-0019-7
3. Intensity and Impact of the New York Railroad Superstorm of May 1921 J. Love et al. https://doi.org/10.1029/2019SW002250
4. Detailed Analysis of Solar Data Related to Historical Extreme Geomagnetic Storms: 1868 – 2010 L. Lefèvre et al. https://doi.org/10.1007/s11207-016-0892-3
5. Reconstructing solar magnetic fields from historical observations A. Pevtsov et al. https://doi.org/10.1051/0004-6361/201834985
6. Long-term studies of photospheric magnetic fields on the Sun A. Pevtsov et al. https://doi.org/10.1051/swsc/2020069
7. The record of the magnetic storm on 15 May 1921 in Stará Ďala (present-day Hurbanovo) and its compliance with the global picture of this extreme event E. Koči & F. Valach https://doi.org/10.5194/angeo-41-355-2023