Content of reference variables. Refers to a data object (data reference) or an instance of a class (object reference). Internally, also strings and internal tables are addressed via references. From the technical point of view, the reference to an object in ABAP occurs on several layers. A reference is an address of an internal header (object header, string header or table header), which contains the address of the actual object and other administrative information such as the data type/> of a referenced data object.