Update README.md

README.md

@@ -11,7 +11,7 @@ pipeline_tag: summarization
 
 ## Description
 Longformer fine-tuned on [MS^2](https://github.com/allenai/mslr-shared-task) for extractive summarization.\
-Model architecture is similar to [BERTSum](https://arxiv.org/abs/1908.08345).\
+Model architecture is similar to [BERTSum](https://github.com/nlpyang/BertSum).\
 Training code is available at [biomed-ext-summ](https://github.com/NotXia/biomed-ext-summ).
 
 ## Usage