<?xml version="1.0"?> <sparql xmlns="http://www.w3.org/2005/sparql-results#"> <head> <variable name="a"/> <variable name="b"/> </head> <results> <result> <binding name="a"> <uri>http://example.com/a</uri> </binding> <binding name="b"> <uri>http://example.com/b</uri> </binding> </result> </results> </sparql>