@article{hede1991self,
  title={Self-affine fractal clusters: Conceptual questions and numerical results for directed percolation},
  author={Hede, B and Kert{\'e}sz, J and Vicsek, T},
  journal={Journal of statistical physics},
  volume={64},
  number={3-4},
  pages={829--841},
  year={1991},
  publisher={Kluwer Academic Publishers-Plenum Publishers}
}