1. R. Halmshaw, “Non-DestructiveTesting”, 2nd Edition (1991) pp 22–24
2. G. Berodias, G. Peix, Materials Evaluation, n°46, (August 1988), pp 1209–1213
3. “Radiographic inspection” in Nondestructive Evaluation and Quality Control, Metals Handbook 9th ed. Vol.17 (1989) p 309.
4. R.S. Holt, M.J. Cooper, British Journal of NDT, (March 1988) pp 75–80
5. C. Le Floch, P. Sarrazin, D. Babot, G. Peix, D. Duvauchelle, 17th Review of Progress in Quantitative NDE, SanDiego, California (USA), (15–20 Jul 1990), Ed. D. O. Thompson & D. E. Chimienti, Plenum