Martin (1992: 110):
Referring to participants by name involves making use of signs which have been assigned to individuals in a community to uniquely identify them. There are obviously more participants than names to go round in most communities and the system is only functional as long as participants in a given context are named differently. Texts assign names to unfamiliar participants where necessary, making use of elaborate structures — for example the identifying clause in [3:30]:
[3:30] There was a little boy. His name was Tommy.
This mistakes the experiential identity of participants for the textual system of reference (which presents items as identifiable).
In [3:30], the only instance of reference is the personal co-reference item his which refers anaphorically to a little boy. Unlike the identifying clause, this cohesive relation expresses "meaning beyond the clause".