Which executive producer of a film 's prequel and sequel executive produced M0 and M1
SELECT DISTINCT ?x0 WHERE {
?x0 ns:film.producer.films_executive_produced ?x1 .
?x0 ns:film.producer.films_executive_produced M0 .
?x0 ns:film.producer.films_executive_produced M1 .
?x1 ns:film.film.prequel ?x2 .
?x1 ns:film.film.sequel ?x2 .
?x2 a ns:film.film
}