5.1 Universal Resource Identifiers (URIs)
 5.2 Universal Resource Locators (URLs)
 5.3 Formal Public Identifiers (FPIs)
 5.4 Uniform Resource Name (URNs)
 5.5 XML Namespaces
 5.6 NameSpaces in SAX
 5.7 Namespace Prefixes
 5.8 Namespace Prefixes in SAX
 5.9 The NamespaceSupport Class
 5.10 Assignment #3: Mini XML Normalization