Lewis, R., Gethin, D., Yang, X., & Lewis, R. (2006). A two dimensional combined discrete and finite element scheme for simulating the flow and compaction of systems comprising irregular particulates. Computer Methods in Applied Mechanics and Engineering, 195(41-43), p. 5552. doi:10.1016/j.cma.2005.10.025

Lewis, Roland, D.T Gethin, X.-S Yang, and R.W Lewis. "A Two Dimensional Combined Discrete and Finite Element Scheme for Simulating the Flow and Compaction of Systems Comprising Irregular Particulates." Computer Methods in Applied Mechanics and Engineering 195, no. 41-43 (2006): 5552.

Lewis, Roland, D.T Gethin, X.-S Yang, and R.W Lewis. "A Two Dimensional Combined Discrete and Finite Element Scheme for Simulating the Flow and Compaction of Systems Comprising Irregular Particulates." Computer Methods in Applied Mechanics and Engineering 195.41-43 (2006): 5552.