Generally speaking we can distinguish the following kind of references:

• Defined directly;

• Defined by the base type

• Derived from the inheritance chain.

It must be clearly stated if the “Part 3 4.5.2 Complex TypeDefinitionNodes and their InstanceDeclarations” applies or not.

Assuming that it is true, usage of the NodeId must be clarified for nodes not included in the xml file in case of partial representation for an arbitrary set of Nodes. According to Part 3; 5.2.2 NodeId: “nodes are unambiguously identified using a constructed identifier called the NodeId” and 8.2 NodeId “This Built-in DataType is composed of three elements that identify a Node within a Server” the NodeId may be dynamically constructed and is unique in context of a server. As it is constructed it is unique in the context of the instance of the Address Space exposed by the server. Part 6 provides NodeId values for well-known types, but is not required for other domain and proprietary definitions. In this case the NodeId may be undefined and finally cannot be referenced by the xml document compliant with the schema.