APA (7th ed.) Citation

Heller, S., & Ruthardt, A. 25 studies for piano, op.47.

Chicago Style (17th ed.) Citation

Heller, Stephen, and Adolf Ruthardt. 25 Studies for Piano, Op.47.

MLA (9th ed.) Citation

Heller, Stephen, and Adolf Ruthardt. 25 Studies for Piano, Op.47.

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