PMC:7696151 / 15188-15326 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T117","span":{"begin":0,"end":138},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Nonetheless, these latter studies have some limitations, such as the small number of subjects included and the absence of a control group."}