- FondsYapp - Papers and photographs of R. H. (Harry) Yapp
- Series2 - Correspondence
- 21 more...
- Subseries22 - Correspondence 1919-20
- Subseries23 - Family letters
- Subseries24 - Swiss trip 1923
- Subseries25 - RHY to Lajla 1920s
- Subseries26 - Final illness and condolences