PMC:7210464 / 5128-5200 JSONTXT

{"project":"LitCovid-PD-CLO","denotations":[{"id":"T25","span":{"begin":42,"end":54},"obj":"http://purl.obolibrary.org/obo/OBI_0000968"}],"text":"el 2014; Wang et al. 2020b), we construct instrumental variables for the"}

{"project":"2_test","denotations":[{"id":"32395017-24789791-64435792","span":{"begin":3,"end":7},"obj":"24789791"}],"text":"el 2014; Wang et al. 2020b), we construct instrumental variables for the"}