role hierarchies in description logic

Is there literature systematically studying extensions of standard 
description logics (AL, or ALC) with role hierarchies?

Thank you for the attention.

Davide

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Davide Grossi
Intelligent Systems Group
Institute of Information and Computing Sciences
Universiteit Utrecht
phone : +31 - 30 - 253 4432
fax   : +31 - 30 - 251 3791
http://www.cs.uu.nl/staff/davide.html 
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Received on Saturday, 25 February 2006 10:23:19 UTC