| RefNo | Title | Source |
| DF/TR/1/1/32/222 | Hertfordshire Natural History Society and Field Club | |
| DF/TR/1/1/31/268 | Hertfordshire Natural History Society and Field Club | |
| DF/TM/1/63/26 | Correspondence H: Hiendlmayr; Hilgert; Hill; Hill & Millard | |
| DF/TM/1/28/7 | Correspondence H: Hill; Holland; Hongkong & Shanghai Banking Corporation; J Honour & Son | |
| DF/TR/1/1/30/236 | Hertfordshire Natural History Society and Field Club | |
| DF/TM/1/20/22 | Correspondence H: Heindlinay; Higlett; Hill | |
| DF/TM/1/35/10 | Correspondence H: Hill; Hilgert; Hollick; Honour & Son | |