SGML
O Standard Generalized Markup Language (SGML) é uma ISO especificação que veio para definir as declarações/sintaxe Linguagens de Marcação.
On the web, HTML 4, XHTML, and XML are popular SGML-based languages. It is worth noting that since its fifth edition, HTML is no longer SGML-based and has its own parsing rules.
Leia mais
- SGML no Wikipedia
- Introducão ao SGML