@inproceedings{Reimann:HORT,
  title = "Hierarchies Of Randomness Tests",
  author = "J. Reimann and F. Stephan",
  booktitle = "Proceedings of the 9th Asian Logic Conference",
  publisher = "World Scientific Publishing",
  year = 2006,
  pdf = "http://math.berkeley.edu/~reimann/Publications/test_hierarchies_preprint.pdf"
}