This section demonstrates some advanced features of AsTeR
that are useful when rendering complex documents. AsTeR
recognizes cross-references and allows the listener to traverse
these as hypertext links. Cross-referenceable objects can be
labeled interactively, and these labels can be used when
referring to such objects within renderings. The ability to
switch among rendering rules enables multiple views and allows
the listener to quickly locate portions of interest in a
document. By activating rendering rules, all instances of a
particular object can be floated to the end of the containing
hierarchical unit, e.g., all footnotes can be floated
to the end of a paragraph. This is convenient when getting a
quick overview of a document. AsTeR also provides a simple
bookmark facility for marking positions of interest to be
returned to later. Finally, AsTeR can be interfaced with
sources of structured information other than electronic
documents. Later, we demonstrate this by interfacing AsTeR to
the Emacs calculator.