Halliday & Matthiessen (2004: 603):
Like expansion, projection is manifested both logically and experientially within the ideational metafunction; but outside the ideational domain, it is manifested interpersonally rather than textually, thus contrasting with the textual manifestation of expansion. That is, while there are conjunctions marking rhetorical relations of elaboration, extension and enhancement, there are no conjunctions marking relations of quoting or reporting; and while there are interpersonal resources for realising projection, there are no interpersonal Adjuncts or other interpersonal manifestations of expansion.