APA (7th ed.) Citation

Morricone, E., & Leone, S. Once Upon a Time in the West: Original Soundtrack Recording. RCA Victor.

Chicago Style (17th ed.) Citation

Morricone, Ennio, and Sergio Leone. Once Upon a Time in the West: Original Soundtrack Recording. [s.l.]: RCA Victor.

MLA (9th ed.) Citation

Morricone, Ennio, and Sergio Leone. Once Upon a Time in the West: Original Soundtrack Recording. RCA Victor.

Warning: These citations may not always be 100% accurate.