PubMed:32112886 / 1481-1483
Annnotations
LitCovid-PAS-Enju
{"project":"LitCovid-PAS-Enju","denotations":[{"id":"EnjuParser_T265","span":{"begin":0,"end":2},"obj":"CD"}],"text":"21"}
LitCovid-TimeML
{"project":"LitCovid-TimeML","denotations":[{"id":"tok302","span":{"begin":0,"end":2},"obj":"CD"}],"text":"21"}