Beethoven, Ludwig van : Quartette, Vl 1 2 Va Vc, op. 131
| Hubert Ries an Louis Spohr in Kassel | Berlin, Freitag 19. Juni 1835 | 1835061940 |
| Hubert Ries an Louis Spohr in Kassel | Berlin, Freitag 3. Juli 1835 | 1835070340 |
| Hubert Ries an Louis Spohr in Kassel | Berlin, Freitag 19. Juni 1835 | 1835061940 |
| Hubert Ries an Louis Spohr in Kassel | Berlin, Freitag 3. Juli 1835 | 1835070340 |