K. Koch, F. Zöllner, and G. Sagerer:

Building a new rotamer library for protein-protein docking using energy calculations and statistical approaches.

In Computer Science and Biology: Proceedings of the German Conference on Bioinformatics, pages 201--202, Braunschweig, Oktober 2001.
The flexibility of amino acid side chain is important for flexible protein docking algorithms. These information can be purchased by scoring different conformations of a side chain by using energy or statistical analysis of side chain changes. Energy minima are calculated (using the AMBER forcefield) and compared to results of the statistical approach. To gain a measurement for flexibility, protein structures of complexed and unbound proteins are compared to detect rotamer changes and torsion angle differences.