<layout>contains a description of ruling technique and layout.
Attributes:
columnsspecifies the number of columns per page
Datatype: CDATA
Values: either a whole number or the string "NA" (not applicable)
Default: '1'
ruledLinesspecifies the number of ruled lines per column
Datatype: CDATA
Values: may be given as a pair of numbers (a range), as a whole number, or as the string "NA" (not applicable)
Default: #IMPLIED
writtenLinesspecifies the number of written lines per colum
Datatype: CDATA
Values: may be given as a pair of numbers (a range), as a whole number, or as the string "NA" (not applicable)
Default: #IMPLIED
Example
<layout ruledLines="25-32">
<p>Most pages have between 25 and 32 long lines ruled in lead.</p>
</layout>
Example
<layout columns="2" ruledLines="42">
<p>2 columns of 42 lines ruled in ink, with central rule 
between the columns.</p>
</layout>
Declaration
<!ELEMENT layout  - -    (p+)>
<!ATTLIST	layout	%a.global;
	columns	CDATA		'1'
			ruledLines	CDATA		#IMPLIED
			writtenLines	CDATA		#IMPLIED>
See further2.6.2. Writing and Notations

Appendix A Reference Documentation for Elements and Classes