Like example, a matter title is looked as contents (SGML) and can be thus composed of anything
Like example, a matter title is looked as contents (SGML) and can be thus composed of anything exprimable in the notation acknowledged for the contents. Moreover, the current definition of the charts of matter navigation (implicitly) allows a reference on an attribute evaluated by reference like a reference on an example of matter relation to refer itself to any identification of SGML (identification including for an example of matter, an example of matter relation, or an information article of the universe of information).