[rules-dev] refactoring drools

Hi, I'm a computer science student and am writing the related-work part for my diploma thesis and would be interested in (scientific) papers or information about refactoring or transformation possibilities which can be done with drools / jboss rules in order to improve design of a knowledge base or simply to delete bad smells. I have to admit that I never worked with drools, as I said I just need that for the related-work part. Could you please give me some hints? Thanks, Franz