Merkede seksjoner forutsetter et 'internt subsett':
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% db-oracle "IGNORE"> <!ENTITY
% db-ibmdb2 "IGNORE"> <!ENTITY
% appserv-websphere "IGNORE"> <!ENTITY
% appserv-silverstream "IGNORE"> <!ENTITY
% os-mswin "IGNORE"> <!ENTITY
% os-solaris "IGNORE"> <!ENTITY
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conceptsoverview.sgm SYSTEM "concepts_with_cond.sgm"> ]> . . . <book
> <title
> Installing on <![%os-mswin;[Microsoft Windows NT/2000]]><![%os-solaris;[Solaris]]> servers running <![%db-oracle;[Oracle]]><![%db-ibmdb2;[IBM DB2]]> database and < ![%appserv-silverstream;[SilverStream]]><![%appserv-websphere;[IBM WebSphere]]> application server </title
> <chapter
> . . . </chapter
> </book
>