<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.1//EN" [ <!ENTITY title SYSTEM "title.sgml"> <!ENTITY history SYSTEM "history.sgml"> <!ENTITY gimp SYSTEM "gimp.sgml"> <!ENTITY cups SYSTEM "cups.sgml"> <!ENTITY utils SYSTEM "utils.sgml"> <!ENTITY gfdl SYSTEM "gfdl.sgml"> ]> <book> &title; &history; &gimp; ∪︀ &utils; &gfdl; </book>