Crossroads 5.3 Copyright Notice
Copyright 1999 by the Association for Computing Machinery, Inc. The
authors of signed articles retain the copyright to their articles.
Permission to make digital or hard copies of part or all of this work for
personal or classroom use is granted without fee provided that copies are
not made or distributed for profit or commercial advantage and that
copies bear this notice and full citation on the first page. Copyrights
for components of this work owned by others than ACM must be honored.
Abstracting with credit is permitted. To copy otherwise, to republish, to
post on servers, or to redistribute to lists, requires prior specific
permission and/or a fee. Request permissions from the authors of the
articles you wish to copy or
crossroads@acm.org.