PMC:7210464 / 20362-20547 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T131","span":{"begin":0,"end":185},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"Other mediating variables include population density, GDP per capita, and the number of doctors at the city level, which we collect from the most recent China city statistical yearbook."}