The hyperref package is used to handle cross-referencing commands in LaTeX to produce some sort of hypertext command; there are backends for the \special set defined for HyperTeX dvi processors, for embedded pdfmark commands for processing by Acrobat Distiller (
dvips
and dvipsone), for dviwindo, for
pdfTeX
, for
TeX4ht
, and for VTEX's pdf and HTML backends.