... customization layers, the changes that you want to make are influenced by the interactions between modules. In these cases, rather than including the whole DTD at once, you include each of the modules ... that may be useful is the alternate version of this book that shows all of the element content models in terms of the parameter entities which define them, rather than the "flattened" ... but using the testing procedure described in Section 5.7," we discovered that these elements are used in other content models. Because they are used in other content modules, they cannot...