updates acknowledgement

README.md

@@ -52,4 +52,9 @@ The top three PCA components accounted for approximately 61%, 10%, and 6% of the
 ![](ClusterAnalysis/clusters3d.png)
 
 ## Contact
-Please contact Phillip.Maraveyias@venafi.com and Ecosystem@Venafi.com if you have any questions about this dataset.
+Please contact phillip.maraveyias@venafi.com and ecosystem@venafi.com if you have any questions about this dataset.
+
+## References and Acknowledgement
+The following papers provided inspiration for this project:
+- Li, J.; Zhang, Z.; Guo, C. Machine Learning-Based Malicious X.509 Certificates’ Detection. Appl. Sci. 2021, 11, 2164. https://doi.org/ 10.3390/app11052164
+- Liu, J.; Luktarhan, N.; Chang, Y.; Yu, W. Malcertificate: Research and Implementation of a Malicious Certificate Detection Algorithm Based on GCN. Appl. Sci. 2022,12,4440. https://doi.org/ 10.3390/app12094440