Assembly Design > Using Assembly > References and Dependencies > Reference Control > About References
  
About References
When you create external references among features in a design, local references to features in a part, or placement references in an assembly, reference creation and backup tools are provided for specifying system behavior.
You can specify global settings that apply to all components in the current session except objects that have an object-specific scope setting and objects that have a less restrictive object-specific scope control. These settings are runtime; that is, they apply only during the session in which they are set. They do not affect the internal database of the object.
You can also specify object-specific scope settings and reference control. This information is stored with the object and is in effect for each assembly in which the object appears.