_:vb50911346	<http://www.w3.org/ns/r2rml#predicateMap>	_:vb50911345 .
_:vb50911346	<http://www.w3.org/ns/r2rml#objectMap>	_:vb50911347 .
_:vb50911345	<http://www.w3.org/ns/r2rml#constant>	<http://xmlns.com/foaf/0.1/lastName> .
_:vb50911347	<http://www.w3.org/ns/r2rml#column>	"last_name" .