@article {1551,
	title = {Surveillance for waterborne-disease outbreaks, United States, 1997-1998},
	journal = {Morbidity and Mortality Weekly Report},
	volume = {49},
	year = {2000},
	chapter = {pp. 1-35},
	author = {Barwick, R S and Levy, D A and Craun, G F and Beach, M J and Calderon, R L}
}
@article {1555,
	title = {Surveillance of waterborne-disease outbreaks, United States, 1999-2000},
	journal = {Morbidity and Mortality Weekly Report},
	year = {2002},
	author = {Lee, S H and Levy, D A and Craun, G F and Beach, M J and Calderon, R L}
}
