[rules-users] 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. I have to admit that I never worked with one of them, as I said I just need that for the related-work part. Could you please give me some hints? Thanks, Franz