Bethmann, Heinrich
| Louis Spohr an Ernst Friedrich Diez in Mannheim | Kassel, Donnerstag 6. Juni 1833 | 1833060615 |
| Karl Feige an Louis Spohr in Marienbad | Kassel, Freitag 12. Juli 1833 | 1833071243 |
| Louis Spohr an Ernst Friedrich Diez in Mannheim | Kassel, Donnerstag 6. Juni 1833 | 1833060615 |
| Karl Feige an Louis Spohr in Marienbad | Kassel, Freitag 12. Juli 1833 | 1833071243 |