PMC:7210464 / 446-623 JSONTXT

{"project":"LitCovid-PD-CLO","denotations":[{"id":"T1","span":{"begin":2,"end":14},"obj":"http://purl.obolibrary.org/obo/OBI_0000968"},{"id":"T2","span":{"begin":171,"end":176},"obj":"http://purl.obolibrary.org/obo/NCBITaxon_10239"}],"text":"s instrumental variables for causal inference. Stringent quarantines, city lockdowns, and local public health measures imposed in late January significantly decreased the virus "}