PMC:6988269 / 72-89
Annnotations
LitCovid-sentences
{"project":"LitCovid-sentences","denotations":[{"id":"T3","span":{"begin":6,"end":16},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"tract\nBackground\n"}