<http://ns.inria.fr/covid19/PMC5079805#body_text>	<http://purl.org/dc/terms/subject>	"Smallpox vaccines" .
<http://ns.inria.fr/covid19/PMC5079805#body_text>	<http://purl.org/dc/terms/subject>	"Physical chemistry" .
<http://ns.inria.fr/covid19/PMC5079805#body_text>	<http://purl.org/dc/terms/subject>	"English letter writers" .