question: What American star of M3 and M4 did M0 and M1 employ
query: SELECT DISTINCT ?x0 WHERE {
  ?x0 ns:film.actor.film/ns:film.performance.film M3 .
  ?x0 ns:film.actor.film/ns:film.performance.film M4 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M0 .
  ?x0 ns:people.person.employment_history/ns:business.employment_tenure.company M1 .
  ?x0 ns:people.person.nationality ns:m.09c7w0
  }