1. Modern Plastics Encyclopedia, Vol. 56, No. 10A (McGraw-Hill, London 1979?1980) pp. 11 and 501
2. B.G. Cartwright, E.K. Shrik, P.B. Price: Nucl. Instrum. Methods153, 457 (1978)
3. Data sheet-PM 002 (Pershore Mouldings Ltd., Worcestershire, U.K.)
4. J.F. Ready (ed.):Industrial Applications of Lasers (Academic Press, New York 1978) pp. 349?361
5. B.L. Gupta, B.S. Narayan, L.M. Kukreja: J. Phys. E13, 1267 (1980)