fix citation formats

README.md

@@ -345,6 +345,7 @@ You can finetune this model on your own dataset.
 ```
 
 #### LIMIT
+```
 @misc{weller2025theoreticallimit,
       title={On the Theoretical Limitations of Embedding-Based Retrieval}, 
       author={Orion Weller and Michael Boratko and Iftekhar Naim and Jinhyuk Lee},
@@ -354,8 +355,10 @@ You can finetune this model on your own dataset.
       primaryClass={cs.IR},
       url={https://arxiv.org/abs/2508.21038}, 
 }
+```
 
 #### OpenSearch Models
+```
 @inproceedings{Shen_2025, series={SIGIR ’25},
    title={Exploring $\ell_0$ parsification for Inference-free Sparse Retrievers},
    url={http://dx.doi.org/10.1145/3726302.3730192},
@@ -367,7 +370,9 @@ You can finetune this model on your own dataset.
    month=jul, pages={2572–2576},
    collection={SIGIR ’25} 
 }
+```
 
+```
 @misc{geng2025competitivesearchrelevanceinferencefree,
       title={Towards Competitive Search Relevance For Inference-Free Learned Sparse Retrievers}, 
       author={Zhichao Geng and Yiwen Wang and Dongyu Ru and Yang Yang},
@@ -377,6 +382,7 @@ You can finetune this model on your own dataset.
       primaryClass={cs.IR},
       url={https://arxiv.org/abs/2411.04403}, 
 }
+```
 
 #### SpladeLoss
 ```bibtex