Update README.md

README.md

@@ -92,7 +92,8 @@ MusicTheoryBench primarily contains English.
 
 ## Limitations
 
-- The MusicThoeryBench results reported in the paper are obtained with perplexity mode.
+- The MusicThoeryBench results reported in [ChatMusician paper](http://arxiv.org/abs/2402.16153) are obtained with perplexity mode. Direct generation may result in a worse performance.
+- See [Opencompass documentaion](https://opencompass.readthedocs.io/en/latest/get_started/faq.html#what-are-the-differences-and-connections-between-ppl-and-gen) for more details.
 
 ## Citation