question: Which person did M1 , M2 , and M3 influence
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 a ns:people.person .
  ?x0 ns:influence.influence_node.influenced_by M1 .
  ?x0 ns:influence.influence_node.influenced_by M2 .
  ?x0 ns:influence.influence_node.influenced_by M3
  }