If you are using results generated with LIGGGHTS®, please cite the following paper:
"Models, algorithms and validation for opensource DEM and CFD-DEM", Christoph Kloss, Christoph Goniva, Alice Hager, Stefan Amberger, Stefan Pirker - Progress in Computational Fluid Dynamics, An Int. J. 2012 - Vol. 12, No.2/3 pp. 140 - 152