_:nc7f594a9bda944dc8bd7f82ac900131cxb4
<http://schema.org/valueRequired>
"true"^^<http://www.w3.org/2001/XMLSchema#boolean>
<https://cybergisxhub.cigi.illinois.edu/notebooks-discovery/?notebook_tag=hydroshare&keywords=sinkhole&author__in=1087>