_:b56902397 <http://www.w3.org/1999/02/22-rdf-syntax-ns#type> <http://www.w3.org/ns/oa#TextQuoteSelector> . _:b56902397 <http://www.w3.org/ns/oa#exact> "frequency" . _:b56902396 <http://www.w3.org/ns/oa#hasSelector> _:b56902397 . _:b56902396 <http://www.w3.org/ns/oa#hasSource> <http://ns.inria.fr/covid19/arg/d185284c60ffb44c2df734cf442cac428501969f/5> .