@article {513691,
	title = {Improving Vignette Descriptions and Question Formats to Measure Distance Vision: Evidence from Cognitive Interviews among Students in China},
	journal = {Field MethodsField Methods},
	year = {2017},
	pages = {1525822X16680810},
	isbn = {1525-822X},
	author = {Su, Yanfang and Willis, Gordon and Joshua A. Salomon}
}
