APA (7th ed.) Citation

Klengel, A. A. 15 lecons progressives: Pour le pianoforte ; op. 21. Erard.

Chicago Style (17th ed.) Citation

Klengel, August Alexander. 15 Lecons Progressives: Pour Le Pianoforte ; Op. 21. Paris: Erard.

MLA (9th ed.) Citation

Klengel, August Alexander. 15 Lecons Progressives: Pour Le Pianoforte ; Op. 21. Erard.

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