1. Hammett, L.P.: Physical Organic Chemistry. New York: McGraw-Hill 1940.
2. Ingold, C.K.: Structure and Mechanism in Organic Chemistry. Ithaca, New York: Cornell University Press 1953.
3. Robertson, J.M.: Organic Crystals. Ithaca: Cornell University Press 1953.
4. Herzberg, G.: Atomic Spectra. New York: Prentice-Hall 1939.
5. Herzberg, G.: Spectra of Diatomic Molecules, 2nd ed. New York: Prentice-Hall 1955.