1. Bruckl, A., and W. Maxymovicz: Z. Anal. Chem. 68, 14 (1926).
2. Feigl, F.: Spot Test in Inorganic Analysis, 5th Edit. Amsterdam: Elsevier, 1958, p. 352
3. Feigl, F.: Spot Test in Inorganic Analysis, 5th Edit. Amsterdam: Elsevier, 1958, p. 378.
4. —, and L. Ben-Dor: Chemist-Analyst 55, 73 (1966).