@article {yu2010evaluating,
	title = {Evaluating China{\textquoteright}s urban environmental sustainability with Data Envelopment Analysis},
	journal = {Ecological Economics},
	volume = {69},
	number = {9},
	year = {2010},
	pages = {1748{\textendash}1755},
	publisher = {Elsevier},
	author = {Yu, Yan and Wen, Zongguo}
}
