Demaq: A Foundation for Declarative XML Message Processing
  This paper gives an overview of Demaq, an XML message processing system operating on the foundation of transactional XML message queues. We focus on the syntax and semantics of its fully declarative, rule-based application language and demonstrate our message-based programming paradigm in the context of a case study. Further, we discuss optimization opportunities for executing Demaq programs. 
Alexander B\"ohm, Carl-Christian Kanne, Guido Moerkotte