1. Becquerel, H.: Compt. Rend. 122, 420 (1896).
2. Davenport, A. N., and G. W. W. Stevens: Brit. J. Appl. Physics 6, 31 (1955).
3. Hald, A.: Statistical Theory with Engineering Applications. New York: J. Wiley & Sons 1962.
4. Malissa, H.: Analytical Chemistry 1962, Proc. Intern. Symposium, p. 80. Amsterdam: Elsevier 1962.
5. Ottendorfer, L. J.: Anal. Chim. Acta 33, 115 (1965).