Halliday & Matthiessen (2004: 489):
Groups and phrases can be linked paratactically by apposition and co-ordination. As with paratactic clauses the former are elaborating in function, the latter extending. Instances of the enhancing type are less common, since the meanings are too specific to be readily expressed as a relationship between units smaller than clauses; but they do occur. There are no paratactic group or phrase complexes linked by projection, except for nominal group complexes such as the examiner’s assessment, ‘a brilliant work’, seems hard to justify, which lie on the borderline of elaborating parataxis.