APA (7th ed.) Citation

Beethoven, L. v. Symphony no. 1, C major, op. 21. Associated Music Publishers.

Chicago Style (17th ed.) Citation

Beethoven, Ludwig van. Symphony No. 1, C Major, Op. 21. New York: Associated Music Publishers.

MLA (9th ed.) Citation

Beethoven, Ludwig van. Symphony No. 1, C Major, Op. 21. Associated Music Publishers.