Halliday & Matthiessen (2014: 390):
What the logical analysis does is to bring out the hypotactic basis of premodification in the nominal group, which then also explains its penchant for generating long strings of nouns … . We refer to this kind of structure as a univariate structure, one which is generated as an iteration of the same functional relationship: a is modified by b, which is modified by c, which is … .