1. A discrete numerical model for granular assemblies;Cundall;Geotechnique,1979
2. Numerical Methods of Engineering, Theory and Applications;Williams,1985
3. Numerical Methods in Rock Mechanics;Pande,1990
4. Williams J R, Pentland A. Super-quadric and modal dynamics for discrete elements in concurrent design. Conference of Discrete Element Methods, U.S. Golden, 1989: 19–20.
5. Discrete element simulation and the contact problem;Williams;Archives of Computational Methods in Engineering,1999