Add literature references to the README.md

README.md

@@ -177,3 +177,9 @@ The steps required to add a new representation scheme are:
 ### Developer
 
 * [Anthony Onwuli](https://github.com/AntObi) (Department of Materials, Imperial College London)
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+
+## References
+[H. Park et al, "Mapping inorganic crystal chemical space" *Faraday Discuss.* (2024)](https://pubs.rsc.org/en/content/articlelanding/2024/fd/d4fd00063c)
+
+[A. Onwuli et al, "Element similarity in high-dimensional materials representations" *Digital Discovery* **2**, 1558 (2023)](https://pubs.rsc.org/en/content/articlelanding/2023/dd/d3dd00121k)