Teiid has a long history from the MetaMatrix product line http://www.jboss.org/teiid/about/history.html. Concepts for the optimizer and processor were derived from many places including standard texts, such as Garcia-Molina - Database System Implementation, open source projects, such as PostgreSQL, and countless research papers. Common key phrases include "data integration", "heterogeneous dbms", "federated dbms", 'query optimization", "access patterns", "rule-based optimization", and even 'eii'. You'll find plenty of university research in federated databases and query optimization, but we don't have a direct lineage from any particular project. Let us know if you need any more details.
Thanks very much!