Self Organized Criticality/Sandpile Models:

Universality in sandpile models,
A. Ben-Hur and O. Biham,
Phys. Rev. E53, R1317 (1996).
Journal   Archive  

Universality classes in isotropic, abelian
and non-abelian sandpile models.
E. Milshtein, O. Biham and S. Solomon,
Phys. Rev. E58, 303 (1998).
Journal       Archive 

Evidence for universality within the classes
of deterministic and stochastic sandpile models.
O. Biham, E. Milshtein and O. Malcai,
Phys. Rev. E63, 061309 (2001).
Journal 

Sandpile models and random walkers on finite lattices.
Y. Shilo and O. Biham,
Phys. Rev. E67, 066102 (2003).
Journal     Archive