docs: Added citation info

README.md

@@ -269,3 +269,19 @@ Recommendation. [Link](https://arxiv.org/pdf/2107.05204)
 ## Author
 
 Thomas van Dongen
+
+## Citation
+
+If you use Pyversity in your research, please cite the following:
+
+```bibtex
+@software{van_dongen_2025_pyversity,
+  author       = {{van Dongen}, Thomas},
+  title        = {Pyversity: Fast Diversification for Search & Retrieval},
+  year         = {2025},
+  publisher    = {Zenodo},
+  doi          = {10.5281/zenodo.17628015},
+  url          = {https://github.com/Pringled/pyversity},
+  license      = {MIT}
+}
+```

citation.CFF

@@ -0,0 +1,23 @@
+cff-version: 1.2.0
+message: "If you use Pyversity in your research, please cite it as below."
+title: "Pyversity: Fast Diversification for Search & Retrieval"
+authors:
+  - family-names: "van Dongen"
+    given-names: "Thomas"
+doi: 10.5281/zenodo.17628015
+license: MIT
+url: "https://github.com/Pringled/pyversity"
+repository-code: "https://github.com/Pringled/pyversity"
+date-released: "2025-10-11"
+
+preferred-citation:
+  type: software
+  title: "Pyversity: Fast Diversification for Search & Retrieval"
+  authors:
+    - family-names: "van Dongen"
+      given-names: "Thomas"
+  year: 2025
+  publisher: Zenodo
+  doi: 10.5281/zenodo.17628015
+  url: "https://github.com/Pringled/pyversity"
+  license: MIT