1. G. Herzberg, Atomic Spectra and Atomic Structure, Dover Publications, New York (1944), p. 142.
2. A. P. Wolf, Adv. Phys. Org. Chem. 2, 201 (1964).
3. R. Wolfgang, Prog. React. Kinet. 3, 97 (1965).
4. R. F. Peterson and R. Wolfgang, Adv. High Temp. Chem. 4, 43 (1971).
5. C. MacKay, in Carbenes, Vol. fl (R. A. Moss and M. Jones, Jr., eds.), Wiley-Inter- science, New York (1975), pp. 1–42.