_:vb50911306	<http://www.w3.org/ns/r2rml#objectMap>	_:vb50911307 .
_:vb50911307	<http://www.w3.org/ns/r2rml#column>	"first_name" .
_:vb50911306	<http://www.w3.org/ns/r2rml#predicateMap>	_:vb50911305 .
_:vb50911305	<http://www.w3.org/ns/r2rml#constant>	<http://xmlns.com/foaf/0.1/firstName> .