@book{3386,
	author = {Vaughan, J. Patrick and World Health Organization},
	title = {Manual of epidemiology for district health management /},
	publisher = {WHO,},
	year = {1989.},
	address = {Geneva :},
	url = {https://apps.who.int/iris/bitstream/handle/10665/37032/924154404X.pdf?sequence=1&isAllowed=y}
}