- FondsYapp - Papers and photographs of R. H. (Harry) Yapp
- Series2 - Correspondence
- 3 more...
- Subseries4 - Davos trip
- Subseries5 - South Africa trip
- Subseries6 - 1909-10 travel
- Subseries7 - Family correspondence
- Subseries8 - Love letters from Lajla to RHY before wedding
- Subseries9 - Letters from RHY to Lajla before their wedding
- Subseries10 - Professional correspondence
- Subseries11 - Letters 1913-14
- Subseries12 - Congratulations upon marriage
- 14 more...