@article {chen2012confidence,
	title = {Confidence intervals for the mean of a population containing many zero values under unequal probability sampling 511: Y},
	journal = {Quality Control and Applied Statistics},
	volume = {57},
	number = {1},
	year = {2012},
	pages = {77},
	author = {Chen, Hanfeng and Chen, Jiahua and Chen, Shun-Yi}
}
