1. G. Herzberg, Vibrational and Rotational Spectra of Polyatomic Molecules [Russian translation], Moscow (1949).
2. G. Herzberg, Electronic Spectra and the Structure of Polyatomic Molecules, Van Nostrand, Princeton (1966).
3. R. M. Hochtrasser, Molecular Aspects of Symmetry, W. A. Benjamin, New York (1966).
4. S. McGlynn, T. Azumi, and M. Kinoshita, Molecular Spectroscopy of the Triplet State, Prentice-Hall, Englewood Cliffs, New Jersey (1969).
5. R. L. Flurry, Symmetry Groups: Theory and Chemical Applications, Prentice-Hall (1980).