1. 1BS EN ISO 12870 (1998 ) Ophthalmic optics. Spectacle frames. General requirements and test methods (dual numbered as BS 6625).
2. 2BS 6625 (1985 )British Standard Specification for Spectacle Frames. HMSO, London.
3. 3D. Bridle (2000 ) Titanium - truth and fiction .Dispensing Opt.November 2000, 14 -15 .
4. 4BS EN 1811 (1999 ) Reference test method for release of nickel from products intended to come into direct and prolonged contact with the skin.
5. 5Consumer Safety Group, Laboratory of the Government Chemist (1998 )Survey of Nickel Release from Spectacle Frames. CACP1, Department of Trade and Industry, London.