1. Harrison G. R., M.I.T. Wavelength Tables (John Wiley and Sons, New York, 1939), p. 302.
2. Spectrographic Analysis of Tungsten Metal Powder
3. Ahrens L. H., Taylor S. R., Spectrochemical Analysis (Addison-Wesley, Reading, Massachusetts, 1961), 2nd ed., Chap. 8, p. 90.
4. Harvey C. E., Spectrochemical Procedures (Applied Research Laboratories, Glendale, California, 1950), Chap. 8, pp. 202–207.
5. Methods for Emission Spectrochemical Analysis, 1982 (ASTM, Philadelphia, Pennsylvania, 1982), p. 793.