2018BS EN 14399-7:2018 High-strength structural bolting assemblies for preloading. System HR. Countersunk head bolt and nut assemblies
2009BS EN 14399-10:2009 High-strength structural bolting assemblies for preloading - Part 10:System HRC - Bolt and nut assemblies with calibrated preload
1969BS 4395-2:1969 Specification for high strength friction grip bolts and associated nuts and washers for structural engineering. Higher grade bolts and nuts and general grade washers