1. Fleury, P., etR. Eberhard: Ann. pharmac. fran�.,16, 465 (1958); cf. Z. analyt. Chem.171, 76 (1959/60).
2. Fox, E. J., andW. J. Geldard: Ind. Engng. Chem.15, 743 (1923); cf. Z. analyt. Chem.69, 181 (1926).
3. La Rosa, C. F.: Rev. Asoc. bioqu�m. argent.23, 228 (1958); cf. Z. analyt. Chem.172, 309 (1960).
4. Morgan, W. A., andE. F. Harford: J. Assoc. off. agric. Chemists41, 637 (1958); cf. Z. analyt. Chem.169, 289 (1959).
5. Watson, D., andD. A. H. Pratt: Lancet1958, II, 1088.