@article{article, title  = {{Temporal and periodic analysis of penumbra–umbra ratio for the last four solar cycles}},

 publisher = {{Springer Science and Business Media LLC}},

 url = {{https://eprints.whiterose.ac.uk/id/eprint/209365 }},

 year = {{2024}},

 month = {{2}},

 author = {{Chowdhury P and Kilcik A and Saha A and Rozelot J-P and Obridko V and Erdélyi R}},

 doi = {{10.1007/s11207-024-02263-5}},

 volume = {{299}},

 journal = {{Solar Physics}},

 issue = {{2}},

 note = {{Accessed on 2025/12/11}}}