Update index.md

Author: monperrus

index.md

@@ -44,7 +44,7 @@ To get notified about project news, subscribe to the [Chains mailing list](https
 (reverse chronological order, newest first)
 
 * 2025
-  - []
+  - [The Design Space of Lockfiles Across Package Managers](http://arxiv.org/pdf/2505.04834). Technical report 2505.04834, arXiv, 2025.
   - [Canonicalization for Unreproducible Builds in Java](https://arxiv.org/abs/2504.21679), Technical report 2504.21679, arXiv, 2025.
   - [Implementing in-toto SBOM Attestations in an Enterprise Context](http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-363613), Master's thesis Christofer Vikström, 2025
   - [Software Bills of Materials in Maven Central](https://arxiv.org/abs/2501.13832), Proceedings of MSR 2025.