Public identifier for Publishers SC variants?

[Scott Hudson <scott.hudson@flatironssolutions.com>]

Based on the description in ch05 
(http://www.docbook.org/tdg/en/html/ch05.html), our variant PI would 
look something like:
-//OASIS//DTD DocBook V5.0-Based Variant For Publishers V1.0//EN

Any suggestions/changes? There may be other variants produced by the SC, 
and could perhaps be handled as:
-//OASIS//DTD DocBook V5.0-Based Variant For Legal Publishers V1.0//EN
-//OASIS//DTD DocBook V5.0-Based Variant For Education Publishers V1.0//EN
-//OASIS//DTD DocBook V5.0-Based Variant For Medical Publishers V1.0//EN

Thoughts?

-- Scott