_:vb50911343	<http://www.w3.org/ns/r2rml#objectMap>	_:vb50911344 .
_:vb50911342	<http://www.w3.org/ns/r2rml#constant>	<http://xmlns.com/foaf/0.1/firstName> .
_:vb50911343	<http://www.w3.org/ns/r2rml#predicateMap>	_:vb50911342 .
_:vb50911344	<http://www.w3.org/ns/r2rml#column>	"first_name" .