ODD chaining - a technique of ordering individual ODD documents in such a way that it is possible for one document to re-use (and potentially modify) declarations and definitions from another document.
For now, one can access an unpublished draft on ODD chaining for beginners, by Lou Burnard (make sure that githubusercontent.com is not blocked by your browser).
Tools for ODD manipulation are available from the TEI Stylesheets package.
See Mapping ODD processing for concise information on ODD-related issues, including chaining.
Other places where one might expect to find information relevant to ODD chaining: