@book{1999,
	author = {Hoshaw-Woodard, Stacy and World Health Organization},
	title = {Description and comparison of the methods of cluster sampling and lot quality assurance sampling to assess immunization coverage /},
	publisher = {WHO,},
	year = {2001.},
	address = {Geneva :},
	url = {http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.409.3852&rep=rep1&type=pdf}
}