References
- Crabtree, J. 1., and Hcnn. R. W . J.S.M.P.T., 65, (1956).
- West, L, E., Phot Sec. Eng., 3, 283, 1959; 9, 398 (1965)
- A.S.A . 238.8.25—1950.
- Mattey, D. A., and Henn. R. W., Phot, sci, Eng., 10, 202 (1966)
- Grainger, F., and Mathewson, H. D., J. Phot Sci., 13, 269 (1965)