@article {5403,
	title = {Efficient Execution of SPARQL Queries With OPTIONAL and UNION Expressions},
	journal = {ArXiv},
	volume = {abs/2303.13844},
	year = {2023},
	doi = {10.48550/arXiv.2303.13844},
	author = {Lei Zou and Yue Pang and Tamer Ozsu and Jiaqi Chen}
}
