Examples of reference objects might include: Customer, Account, Telephone Switch, and the like. They are often complex and large and may be referred to in lots of places. They usually have a rich state and any change from any place needs to be visible to other objects that refer to it.
Reference objects are compared based on their identity, although you may see identifying attributes. You don't usually see multiple copies of the same ReferenceObject in one address space.
Reference objects typically will have the following attributes:
The EqualityOperator is the same as the identity operator (two reference objects are equal if and only if they are identical)