_:b57753760	<http://www.w3.org/ns/oa#hasSource>	<http://ns.inria.fr/covid19/arg/c1aefcef321326189d24aaa2fd4217171aab3e96/1> .
_:b57753760	<http://www.w3.org/ns/oa#hasSelector>	_:b57753761 .
_:b57753761	<http://www.w3.org/ns/oa#exact>	"difficulty" .
_:b57753761	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/oa#TextQuoteSelector> .