Add citation

README.md

@@ -31,3 +31,22 @@ pipe = transformers.pipeline(model=model_name)
 text = "Olá, como você está?"
 print(pipe(text))
 ```
+
+## Citation
+
+If you use this model in your work, please cite the following paper:
+
+```
+@article{Sousa2025,
+   author = {Hugo Sousa and Rúben Almeida and Purificação Silvano and Inês Cantante and Ricardo Campos and Alipio Jorge},
+   doi = {10.1609/aaai.v39i24.34705},
+   issn = {2374-3468},
+   issue = {24},
+   journal = {Proceedings of the AAAI Conference on Artificial Intelligence},
+   month = {4},
+   pages = {25192-25200},
+   title = {Enhancing Portuguese Variety Identification with Cross-Domain Approaches},
+   volume = {39},
+   year = {2025}
+}
+```