{ "head": {
    "vars": [ "p" , "q" ]
  } ,
  "results": {
    "bindings": [
      { 
        "p": { "type": "uri" , "value": "http://example/b" } ,
        "q": { "type": "uri" , "value": "http://example/q" }
      }
    ]
  }
}
