APA (7th ed.) Citation

Chopin, F., & Friedman, I. Ballade no. 4 in A flat, As-Dur, op. 47.

Chicago Style (17th ed.) Citation

Chopin, Frédéric, and Ignacy Friedman. Ballade No. 4 in A Flat, As-Dur, Op. 47.

MLA (9th ed.) Citation

Chopin, Frédéric, and Ignacy Friedman. Ballade No. 4 in A Flat, As-Dur, Op. 47.

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