These are the ADX2.1 schema documents. 
These describe documents with the identical structure as ADX2, however 
1. the base and utility classes have been replaced by references to GML components
2. the invalid OASIS CIQ components have been replaced by ISO DTS 19139 CI_Citation references
The ADX2.1 schema is valid according to XML Spy and Xerces C++ validators. 

Note that the schema has dependencies on the following additional components:
A. the GML schema, with the web-addressible location http://schemas.opengis.net/gml/3.1.1/base/gml.xsd
B. parts of the ISO DTS 19139 metadata schema, available from the same repository as ADX from the relative paths ../../iso19139/gco/gco.xsd and ../../iso19139/gmd/citation.xsd

This repository is maintained in Subversion. 
Web access is open, but for direct access using a Subversion client, please contact Simon.Cox@csiro.au for an account. 

SJDC 2005-11-17