In which papers are energy system scenarios used that consider the 2050 time frame?
SELECT ?paper
WHERE {
  {
    orkgr:R150337 orkgp:compareContribution ?contrib.
  } UNION {
    orkgr:R153801 orkgp:compareContribution ?contrib.
  }
  ?paper orkgp:P31 ?contrib.
  {
     ?contrib orkgp:P37586 ?scenarios.
     ?scenarios orkgp:P37675 ?studies.
     ?studies orkgp:P35205 ?timeframes.
  } UNION {
     ?contrib orkgp:P37581 ?scenario.
     ?scenario orkgp:P43138 ?goal.
     ?goal orkgp:P43139 ?timeframes.
  }
  FILTER(xsd:int(?timeframes) = 2050)
}