_:b57811937	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/oa#TextQuoteSelector> .
_:b57811937	<http://www.w3.org/ns/oa#exact>	"optical density" .
_:b57811936	<http://www.w3.org/ns/oa#hasSource>	<http://ns.inria.fr/covid19/arg/1f09630649c6584bb2b34d55e282e31328fe466d/0> .
_:b57811936	<http://www.w3.org/ns/oa#hasSelector>	_:b57811937 .