@book{12979,
	author = {Boerma, Jan Ties and Sommerfelt, A. Elisabeth and Macro International. Institute for Resource Development . Demographic and Health Surveys.},
	title = {Immunization : levels, trends and differentials.},
	publisher = {Institute for Resource Development/Macro Systems,},
	year = {1990.},
	series = {Demographic and health surveys comparative studies ; no.1.},
	address = {Columbia, MD : }
}