1. [1] Asadi, Arash; Backman, Spencer Chip-firing and Riemann–Roch Theory for Directed Graphs (2010) (https://arxiv.org/abs/1012.0287)
2. [2] Backman, Spencer; Manjunath, Madhusudan Explicit deformation of lattice ideals via chip-firing games on directed graphs, J. Algebraic Combin., Volume 42 (2015) no. 4, pp. 1097-1110
3. [3] Bak, Per; Tang, Chao; Wiesenfeld, Kurt Self-organized criticality, Phys. Rev. A (3), Volume 38 (1988) no. 1, pp. 364-374
4. [4] Berkesch, Christine; Schreyer, Frank-Olaf Syzygies, finite length modules, and random curves (2014) (https://arxiv.org/abs/1403.0581)
5. [5] Brualdi, Richard A.; Ryser, Herbert J. Combinatorial matrix theory, Cambridge University Press, Cambridge, Encyclopedia of Mathematics and its Applications, Volume 39 (1991), x+367 pages