Descriptions at:
   * ''Data Compression'' [http://www.ics.uci.edu/~dan/pubs/DataCompression.html]
   * ''Dr. Dobb's'' article [http://dogma.net/markn/articles/arith/part1.htm], with sample C code
   * [Elias coding]
   * [Fibonacci coding]

Closely related is the ''Range Encoder'', see [http://www.compressconsult.com/rangecoder/]