The two men have collaborated on seven films.

The two men also collaborated on writing songs.

The two men would collaborate by testing for Harvard's national scholarships.

That the two men collaborated in Hollywood from 1938 through 1947 was bound to have produced significant and interesting results.

The two men collaborated to save the historic Gibraltar structure.

It was the first of eleven projects on which the two men collaborated.

Since then the three men have collaborated several times.

The two men are now collaborating on a fourth album, which they plan to release later this year.

The two men later collaborated on works about the media treatment of postwar Indochina, Cambodia in particular.

The two men dined together regularly and even collaborated on a book.