@article {5219,
	title = {Sparsifying Sparse Representations for Passage Retrieval by Top-K Masking},
	journal = {ArXiv},
	volume = {abs/2112.09628},
	year = {2021},
	url = {https://arxiv.org/abs/2112.09628},
	author = {Jheng-Hong Yang and Xueguang Ma and Jimmy Lin}
}
