In fact, there is at present an international effort being made of
the development of what is called the `Standard Generalized Mark-up
Language' (SGML).
SGML will be / is an ISO standard.
SGML will be mainly used by publishers and by organisations to maintain
large databases.
As an author you do not have to worry that you will yet again have
to learn something new: suppliers of word-processors will incorporate
SGML in their products, so you will produce SGML manuscripts without
knowing it.