Martin (1992: 113):
This subclassification of undirected reference is outlined systemically in Fig. 3.7. Reference to a [superset] is made optional; then [selective] reference to a particular member of the superset is contrasted with [non-selective] reference; the remaining options break down selective and non-selective reference as these have been described (the recursivity of the [quality] feature is not shown).
 The notion of 'undirected reference' is an oxymoron. Reference items refer to referents.
 In addition to being based on the misunderstandings identified in the preceding posts, the system provides no realisation statements that specify either:
- how these features are realised syntagmatically at the level of discourse semantics, or
- how the discourse semantic features are realised at the level of lexicogrammar.