Hummel, Johann Nepomuk : Mathilde von Guise
| Carl Friedrich Peters an Louis Spohr in Kassel | Leipzig, Freitag 18. Juli 1823 | 1823071850 |
| Louis Spohr an Wilhelm Speyer in Frankfurt am Main | Kassel, Freitag 23. August 1833 | 1833082302 |
| Carl Friedrich Peters an Louis Spohr in Kassel | Leipzig, Freitag 18. Juli 1823 | 1823071850 |
| Louis Spohr an Wilhelm Speyer in Frankfurt am Main | Kassel, Freitag 23. August 1833 | 1833082302 |