PMC:7210464 / 424-486
Annnotations
LitCovid-PD-CLO
{"project":"LitCovid-PD-CLO","denotations":[{"id":"T1","span":{"begin":24,"end":36},"obj":"http://purl.obolibrary.org/obo/OBI_0000968"}],"text":"weeks prior are used as instrumental variables for causal infe"}