1. Lecomte, Traité de Chimie Organique (ed. Grignard et Baud, Masson et Cie, Paris, 1936), 2, 143.
2. Colthup, J. Opt. Soc. Amer., 1950, 40, 397.
3. Barnes Gore, Liddel and Van Zandt Williams, Infra-red Spectroscopy (Reinhold, 1944 ).
4. Randall, Fowler, Fuson and Dangl, Infra-red Determination of Organic Structures (Van Nostrand, 1949 ).
5. Herzberg, Infra-red and Raman Spectra of Polyatomic Molecules (Van Nostrand, 1945), p. 340.