1. PISC Plate Inspection Steering Committee. CEC Report EUR 6371 Vol I-V 1979. Note: acronym now stands for Programme for the Inspection of steel components.
2. Cook D. Brit. Ac Soc. Spring Meeting. Loughborough 1972.
3. Böttcher B., Schulz E. and Wüstenberg H. A new method of crack depth determination in ultrasonic materials testing. Proc. 7th International Conf. on NDT. Warsaw, 1973.
4. Silk M.G. and Liddington B.H. An investigation of the potential use of scattered ultrasound in the determination of crack depth. AERE-R 7649. 1974.