PMC:7795931 / 40946-41146 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T258","span":{"begin":0,"end":200},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"The information dissemination network and the physical-layer contact network are not precisely observable in the real world, which makes it challenging for acquiring sufficient data for model fitting."}