What did a person executive produce and M0 and M1 executive produce
SELECT DISTINCT ?x0 WHERE {
?x0 ns:film.film.executive_produced_by ?x1 .
?x0 ns:film.film.executive_produced_by M0 .
?x0 ns:film.film.executive_produced_by M1 .
?x1 a ns:people.person
}