Assertion: polio | /r/HasProperty | united states
Facets:
Source sentences:
text: Poliomyelitis – United States, 1950-2011 Source:
text: Poliomyelitis – United States, 1980-2010
text: Poliomyelitis -- United States, Canada MMWR 1979;28:229-30 (May 25, 1979)