| 16E19112 | U1725 | MINISTRY OF DEFENCE AIR DOMESTIC R FERENCE NUMBER USE ONLY |
| BS57 | K7766 | BRITISH STANDARDS INSTITUTION |
| ND33671 | K0207 | HALE HAMILTON (VALVES) LIMITED |
| BS57-TABLE 1 | K7766 | BRITISH STANDARDS INSTITUTION |
| NS37-10Z1 | U0041 | PRESTOLITE ELECTRIC LIMITED TEMS |