Acknowledgement

The authors thank P. Zegeling for many fruitful discussions. They are grateful to the Deutsche Forschungsgemeinschaft and the International Research and Training Group on Nonlinearities and Upscaling (IRTG NUPUS) for financial support.

Authors:	R. Hilfer and F. Doster
originally published in:	Transport in Porous Media, Vol. 82, Issue 3, pages 507-519 (2010)
originally submitted:	July 23rd, 2009