Add citation section

Author: Ivo Djidrovski

README.md

@@ -332,3 +332,9 @@ _OECD QSAR Toolbox is proprietary software. Users must supply their own licensed
 ## Acknowledgements / Origins
 
 This work was developed in the context of the **VHP4Safety** project and related efforts. It builds on upstream third-party data/services (see repository documentation for exact dependencies and access requirements).
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+## Cite
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+If you use ToxMCP in your work, please cite the preprint: https://doi.org/10.64898/2026.02.06.703989
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+Citation metadata: [CITATION.cff](./CITATION.cff)