http://www.loc.gov/mods/v3 http://www.loc.gov/standards/mods/v3/mods-3-2.xsd
Guide to calibration and settingup of the ultrasonic time of flight diffraction [TOFD] technique for the detection, location and sizing of flaws
"This British standard, having been prepared under the direction of the Welding Standards Policy Committee, was published under the authority of the Standards Board and comes into effect on 15 December 1993"