<?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>