ChemDraw Chem3D: I need some MM2 references

I need some MM2 references.

The following reference gives a set of procedures and guidelines for estimation of bond length, bond angle and torsional potential constants for molecular mechanics force fields. The force field constants are ultimately derived by "subtracting" non-bonded molecular mechanics energies from the molecular orbital energies using a model compound containing the chemical structure to be parameterized. "A Molecular Mechanics Valence Force Field for Sulfonamides Derived by ab Initio Methods", JB Nicholas et al, JPhysChem, 1991, 95, 9803-11. is a recent example of the method.