_:vb50911235	<http://www.w3.org/ns/r2rml#predicateMap>	_:vb50911234 .
_:vb50911236	<http://www.w3.org/ns/r2rml#column>	"last_name" .
_:vb50911235	<http://www.w3.org/ns/r2rml#objectMap>	_:vb50911236 .
_:vb50911234	<http://www.w3.org/ns/r2rml#constant>	<http://xmlns.com/foaf/0.1/lastName> .