Martin (1992: 19):
In Cohesion In English terms, structure is concerned with relationships within the sentence, cohesion with relationships between them.
This is not true. In Systemic Functional grammar, multivariate structures pertain to rank units, such as the clause, and univariate structures to unit complexes, such as the clause complex.
Cohesive relations can obtain both within and between clauses and clause complexes. Examples include substitution or ellipsis in the secondary clause of a clause nexus, or anaphoric reference or lexical cohesion within a clause nexus.