1. MNDO: Dewar, M. J. S.; Thiel, W. J. Am. Chem. Soc., 1977, 99, 4899, 4907.
2. AM1: Dewar, M. J. S.; Zoebisch, E. G.; Healy, E. F.; Stewart, J. J. P. J. Am. Chem. Soc., 1985, 107, 3902.
3. PM3: Stewart, J. J. P. J. Comput. Chem., 1989, 10, 209.
4. MOPAC, a program containing all of the above methods: Stewart, J. J. P. J. Comp-Aided. Mol. Design, 1990, 4, 1.
5. Jensen, F., Introduction to Computational Chemistry, Wiley, 1999; Chapter 3.
6. Cramer, C. J., Essentials of Computational Chemistry, Wiley, 2003; Chapter 5.