1. Nelson, W. R., Hirayama, H. and Rogers, D. W. O. (1985) The EGS-4 code system, SLAC-Report-265
2. Subbaiah, Dr. K.V., Private communication, IGCAR, Kalpakkam
3. Measurement of Absolute Thick Target Bremsstrahlung Spectra;O'Dell;Nucl. Instr. Methods,1968
4. Data for Use in Protection against External Radiation (1987), ICRP Publication 51, Pergamon Press, Oxford
5. In Engineering Compendium on Radiation Shielding Vol. 1, R.G. Jaeger (ed.), Springer-Verlag, New York, (1968)