README: add Zenodo DOI badge + BibTeX with DOI (10.5281/zenodo.20363013)

README.md

@@ -26,8 +26,12 @@ pretty_name: Wikidata × OpenRegistry company alignment
 
 # Wikidata × OpenRegistry company alignment
 
+[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.20363013.svg)](https://doi.org/10.5281/zenodo.20363013)
+
 A precomputed map between **Wikidata items for companies** and their **canonical OpenRegistry URLs**.
 
+**Cite as**: Sophymarine (2026). *Wikidata × OpenRegistry company alignment* (Version 1.0.0) [Data set]. Zenodo. https://doi.org/10.5281/zenodo.20363013
+
 For every Wikidata item that has at least one supported national company-registry identifier statement, this dataset provides a single row giving the QID, the registry identifier, and the corresponding direct URL on OpenRegistry — the multi-registry gateway operated by Sophymarine, licensed by UK Companies House, Ireland CRO, Norway Brønnøysundregistrene, Switzerland Zefix, Corporations Canada, Netherlands KvK, Australia ABR, France Sirene, Finland PRH, Czechia ARES, Poland KRS, Belgium KBO, Isle of Man Companies Registry and others.
 
 The alignment was built by querying the [Wikidata Query Service](https://query.wikidata.org/) on 2026-05-24 for each of 17 national company-identifier properties and combining the results.
@@ -109,16 +113,23 @@ OpenRegistry URLs are public addresses; reusing them carries no additional restr
 
 ## Citation
 
-```
+```bibtex
 @dataset{wikidata_openregistry_alignment_2026,
-  title  = {Wikidata × OpenRegistry company alignment},
-  author = {Sophymarine},
-  year   = {2026},
-  url    = {https://openregistry.sophymarine.com},
-  note   = {CC0; snapshot 2026-05-24}
+  title     = {Wikidata × OpenRegistry company alignment},
+  author    = {Sophymarine},
+  year      = {2026},
+  month     = {may},
+  publisher = {Zenodo},
+  version   = {1.0.0},
+  doi       = {10.5281/zenodo.20363013},
+  url       = {https://doi.org/10.5281/zenodo.20363013}
 }
 ```
 
+Mirrors:
+- HuggingFace Datasets: <https://huggingface.co/datasets/Sophymarine/wikidata-alignment>
+- Zenodo (with DOI): <https://doi.org/10.5281/zenodo.20363013>
+
 ## Source
 
 OpenRegistry — multi-registry gateway: <https://openregistry.sophymarine.com>