1. Reliability of Photoelectric Photometry
2. Sherman J., Physical Methods in Chemical Analysis, Berl W. G., Ed. Academic Press, Inc., New York, 1950, p. 327
3. Conditions for securing accuracy in spectrophotometry
4. Harrison G. R., Lord R. C., and Loofbourow J. R., Practical Spectroscopy, Prentice Hall, New York, 1948, p. 359