HyTime
Hypermedia/Time-based Structuring Language: an emerging
ANSI/ISO Standard from the {SGML} Users' Group's Special
Interest Group on Hypertext and Multimedia (SIGhyper). A
hypermedia extension of {SGML}.
["The HyTime Hypermedia/Time-based Document Structuring
Language", S. Newcomb et al, CACM 34(11):67-83 (Nov 1991)].