1. Vanossi, R.: An. Soc. ci. argent. 153, 49 (1952).
2. Young, R.S.: Analyst 76, 49 (1951).
3. Ayres, G.H., Tuffly, B.L.: Analyt. Chem. 24, 949 (1952).
4. Ballou, N.E.: ref. in Lit. Nr. [5].
5. Coryell, C.D., Sugarman, N.: Radiochemical Studies: The fission products, p. 1563. New York: McGraw-Hill Book Co. Inc. 1951.