| 16B6812 | U1725 | MINISTRY OF DEFENCE AIR DOMESTIC R FERENCE NUMBER USE ONLY |
| 17-27B | 99237 | AIRFORCE-NAVY AERONAUTICAL DESIGN STANDARD |
| R4118P5 | K0640 | FREUDENBERG TECHNICAL PRODUCTS |
| BS1806-217 | K7766 | BRITISH STANDARDS INSTITUTION |
| BSM48-217 | K7766 | BRITISH STANDARDS INSTITUTION |