- FondsPP - Helen Martens fonds
- Series4 - Felix Mendelssohn research
- 6494 - Untitled
- File1 - Photocopies of transcribed letters from Mendelssohn to Horsleys
- File2 - Annotated research
- File3 - Notes on mentions of Mendelssohn in newspaper
- File4 - Research on Mendelssohn
- File5 - Research on Mendelssohn’s concerts
- File6 - Photocopy of transcribed letters between Mendelssohn and F. David
- File7 - Research on Mendelssohn’s tutor J.G. Droysen
- File8 - Research on Eduard Devrient’s memoir of Mendelssohn
- File9 - Photocopies of newspaper articles concerning Mendelssohn.
- 48 more...