Each of these structures conveys information, through its form and associated content detail, about what is more or less important in the source text from the relevant point of view, and can therefore be used for summarizing.
the linguistic structure leads to a contrastive summary emphasizing key book-type features (LS), the communicative structure to a justification for action summary (CS), and the world structure to a simple descriptive summary (WS), without the presentational or functional character of the other two.