@book{8117,
	author = {WHO Expert Committee on Health Statistics (1972 : Geneva). and World Health Organization},
	title = {Statistical principles in public health field studies : fifteenth report of the WHO Expert Committee on Health Statistics [meeting held in Geneva from 21 to 27 March 1972].},
	publisher = {World Health Organization,},
	year = {1972.},
	series = {(WHO technical report series ; 510)},
	address = {Geneva : }
}