1. M.L. Franklin, G. Horlick,and H.V. Malmstadt, Anal.Chem., 41, 2 (1969).
2. H.V. Malmstadt, M.L. Franklin, and G. Horlick, Anal.Chem., 44, No. 8, 63A (1972).
3. G.A. Morton, App. Opt., 7, 1 (1968).
4. ORTEC., Inc., Bulletin on Model 5C1 Photon Counting System, Oak Ridge, TN. (1973).
5. M.R. Zatzick, SSR Instruments Co., Applications Note 71021, Santa Monica, Ca.