1. LKB Reference (shelfmark): LKB Title: Correspondence Scope & Content: Correspondence with family, friends, colleagues and publishers. Some undated documents Collection Area: Sound Archive Languages: English and German Date Range: Mid 20th century Extent: 7 files
2. LKB2 Reference (shelfmark): LKB2 Title: Letters from Koch Scope & Content: Correspondence to colleagues, family and the BBC Collection Area: Sound Archive Languages: English and German Date Range: 1953-1963 Extent: 77 folios
3. LKB1 Reference (shelfmark): LKB1 Title: Correspondence from family and friends Scope & Content: Correspondence from family and friends including letters and cards, and some brochures Collection Area: Sound Archive Languages: English and German Date Range: Mid 20th century Extent: 67 folios and 18 items
4. LKB1.1 Reference (shelfmark): LKB1.1 Title: Correspondence from family members Scope & Content: Correspondence, letters and postcards from friends, family and colleagues [some German] Collection Area: Sound Archive Languages: English and German Date Range: 1945-1967 Extent: 67 folios