_:vb51208523	<http://www.w3.org/2007/05/powder-s#describedby>	<https://demo.openlinksw.com/about/id/entity/http/demo.openlinksw.com/r2rml_claude_2> .
_:vb51208523	<http://www.w3.org/ns/r2rml#constant>	<http://demo.openlinksw.com/schemas/claude_northwind#graph> .