1. D. M. Hubbard, “Determination of Bismuth in Biological Material-Photometric Dithizone Method,” Ind. Eng. Chem., Anal, Ed. 11:343 (1939).
2. D. M. Hubbard, “Microdetermination of Bismuth in Biological Materials,” Anal, Chem. 20: 363 (1948).
3. H. Steinberg et al., “Industrial Exposures to Tellurium: Atmospheric Studies and Clinical Evaluation,” J. Ind. Hyg, Toxicol. 24: 183 (1942).
4. E. B. Sandell, Colorimetric Determination of Traces of Metals, Interscience Publishers, Inc., New York (1959), Chap. X.
5. David F. Boltz, Colorimetric Determination ofNonmetals, Interscience Publishers, Inc., New York (1958), Chap. X.