| HALS | Local history reference | Frederic Osborn Collection | Not for loan (Set: 14 Dec 2011) |
| Hemel Hempstead Library | Local history reference | 307 | Not for loan (Set: 14 Dec 2011) |
| Welwyn Garden City Library and Information Service | Local history reference | LOC P 307.768 N.T. | Not for loan (Set: 14 Dec 2011) |