PubMed:32062957 / 972-974
Annnotations
LitCovid-TimeML
{"project":"LitCovid-TimeML","denotations":[{"id":"tok199","span":{"begin":0,"end":2},"obj":"CD"}],"text":"21"}
MeasurableQuantitativeAnnotation
{"project":"MeasurableQuantitativeAnnotation","denotations":[{"id":"N5","span":{"begin":0,"end":2},"obj":"num"}],"text":"21"}