1<!ELEMENT letter-order (head?, body)> 2<!ATTLIST letter-order version CDATA #REQUIRED> 3 4 <!ELEMENT head (create | title | comment | generator)*> 5 6 <!ELEMENT create EMPTY> 7 <!ATTLIST create user CDATA #IMPLIED> 8 <!ATTLIST create host CDATA #IMPLIED> 9 <!ATTLIST create date CDATA #IMPLIED> 10 <!ATTLIST create source CDATA #IMPLIED> 11 12 <!ELEMENT title (#PCDATA)> 13 14 <!ELEMENT comment (#PCDATA)> 15 16 <!ELEMENT generator EMPTY> 17 <!ATTLIST generator name CDATA #REQUIRED> 18 <!ATTLIST generator version CDATA #REQUIRED> 19 20 <!ELEMENT body (area?, order+)> 21 22 <!ELEMENT area EMPTY> 23 <!ATTLIST area width CDATA "16"> 24 <!ATTLIST area height CDATA #IMPLIED> 25 26 <!ELEMENT order (#PCDATA | sp | null)*> 27 28 <!ELEMENT sp EMPTY> 29 30 <!ELEMENT null EMPTY> 31