PMC:7463108 / 4594-4689 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T39","span":{"begin":0,"end":95},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"The first phase began in the late 1990s with an increase in the number of prescription opioids."}