1. See any modern textbook in Organic Chemistry; Lindner H.J., Naturwissenschaften, 61 (1977) 177.
2. Náray-Szabó G., Surján P.R. and Angyán J.G., Applied Quantum Chemistry, D. Reidel Publishing Company, Dordrecht, 1987; Ahlrichs, R., Nachr. Chem. Tech. Lab., 36 (1988) 738.
3. Allinger N.L., Adv. Phys. Org. Chem., 13 (1976) 1; Burkert, U. and Allinger, N.L., Molecular Mechanics, American Chemical Society, Washington, DC, 1982.
4. Powell R.E., J. Chem. Educ., 45 (1968) 558, 790.
5. Brickmann J., J. Spectrosc., 7 (1986) 1.