Define UDN and add citation

README.md

@@ -50,7 +50,7 @@ The full RARE-PHENIX workflow includes additional downstream modules for HPO sta
 
 This adapter was fine-tuned on the public RareDis corpus.
 
-It is **not** the full UDN-trained RARE-PHENIX model described in the manuscript. Controlled-access UDN data and UDN-trained model artifacts are not included.
+It is **not** the full Undiagnosed Diseases Network (UDN)-trained RARE-PHENIX model described in the manuscript. Controlled-access Undiagnosed Diseases Network (UDN) data and UDN-trained model artifacts are not included.
 
 ## Base model
 
@@ -123,4 +123,7 @@ This adapter is intended for research use in rare disease phenotype extraction w
 
 ## Citation
 
-If you use this model, please cite the RARE-PHENIX manuscript and the GitHub repository.
+If you use this adapter, please cite:
+
+Shyr, C., Hu, Y., Tinker, R.J., Cassini, T.A., Byram, K.W., Hamid, R., Fabbri, D.V., Wright, A., Peterson, J.F., Bastarache, L., and Xu, H. 2026. *An artificial intelligence framework for end-to-end rare disease phenotyping from clinical notes using large language models*. arXiv preprint arXiv:2602.20324.
+