_:n214c383116e044c9865d2f9b1293adbexb1
<http://schema.org/isAccessibleForFree>
"true"^^<http://www.w3.org/2001/XMLSchema#boolean>
<https://jfootankleres.biomedcentral.com/articles/10.1186/s13047-015-0110-9/tables/3>