APA (7th ed.) Citation

Schumann, R., Schumann, R., & Schumann, R. (1993). Myrthen: Op. 25. Delta Music.

Chicago Style (17th ed.) Citation

Schumann, Robert, Robert Schumann, and Robert Schumann. Myrthen: Op. 25. Frechen: Delta Music, 1993.

MLA (9th ed.) Citation

Schumann, Robert, et al. Myrthen: Op. 25. Delta Music, 1993.