    <!--
    SRGS XML Grammar Form DTD (20031204)

    Copyright 1998-2003 W3C (MIT, ERCIM, Keio), All Rights Reserved.

    Permission to use, copy, modify and distribute the SRGS DTD and
    its accompanying documentation for any purpose and without fee is
    hereby granted in perpetuity, provided that the above copyright
    notice and this paragraph appear in all copies.

    The copyright holders make no representation about the suitability
    of the DTD for any purpose. It is provided "as is" without expressed
    or implied warranty.

    -->
    <!ENTITY % uri "CDATA">
    <!ENTITY % rule-expansion "#PCDATA | token | ruleref
                                  | item | one-of | tag ">
    <!ENTITY % grammar-header "( meta | metadata | lexicon | tag )*">
    <!ENTITY % grammar-body "( rule )*">
    <!ELEMENT ruleref EMPTY>
    <!ATTLIST ruleref
        uri %uri; #IMPLIED
        type CDATA #IMPLIED
        special (NULL | VOID | GARBAGE) #IMPLIED
    >
    <!ELEMENT token (#PCDATA)>
    <!ATTLIST token
        xml:lang NMTOKEN #IMPLIED
    >
    <!ELEMENT tag (#PCDATA)>
    <!ELEMENT one-of (item)+>
    <!ATTLIST one-of
        xml:lang NMTOKEN #IMPLIED
    >
    <!ELEMENT item (%rule-expansion;)*>
    <!ATTLIST item
        repeat NMTOKEN #IMPLIED
        repeat-prob NMTOKEN #IMPLIED
        weight NMTOKEN #IMPLIED
        xml:lang NMTOKEN #IMPLIED
    >
    <!ELEMENT rule (%rule-expansion; | example)*>
    <!ATTLIST rule
        id ID #REQUIRED
        scope (private | public) "private"
    >
    <!ELEMENT example (#PCDATA)>
    <!ELEMENT lexicon EMPTY>
    <!ATTLIST lexicon
        uri %uri; #REQUIRED
        type CDATA #IMPLIED
    >
    <!ELEMENT meta EMPTY>
    <!ATTLIST meta
        name NMTOKEN #IMPLIED
        content CDATA #REQUIRED
        http-equiv NMTOKEN #IMPLIED
    >
    <!ELEMENT metadata EMPTY>
    <!ELEMENT grammar (%grammar-header;, %grammar-body;)>
    <!ATTLIST grammar
        tag-format %uri; #IMPLIED
        xml:base %uri; #IMPLIED
        version NMTOKEN #REQUIRED
        xml:lang NMTOKEN #IMPLIED
        xmlns CDATA #FIXED 'http://www.w3.org/2001/06/grammar'
        xmlns:xsi CDATA #IMPLIED
        xsi:schemaLocation CDATA #IMPLIED
        root IDREF #IMPLIED
        mode (voice | dtmf) "voice"
    >