PMC:7796152 / 25670-25798 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T209","span":{"begin":0,"end":128},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"One is the cross-sectional study design, which does not allow for the prediction of a causal relationship between the variables."}