However I would disagree with your recommendation to re-use other schemas when modelling XML. I recommend that you use your own element names when data modelling a particular domain. As long as there is a 'semantic' link, explicitly declared or otherwise, for example between my <author/> and Dublin core <creator/>, then I can easily transform my schema and my look at the world into a more interoperable markup say using XSLT. This indirection will avoid problems when so called 'standards' like Dublin Core change, which they inevitably do. Using schemas outside your physical control in mission critical applications is very risky.