The 
                  lnum element represents the line number of the parent 
                  
                     ln
                     .
                  
               
               Line numbers are a common convention in poetic works, legal texts and programming code.
             
            
               optional attributes: 
@about, 
                  
@by, 
                  
@class, 
                  
@content, 
                  
@datatype, 
                  
@desc, 
                  
@its:dir, 
                  
@its:translate, 
                  
@property, 
                  
@rel, 
                  
@resource, 
                  
@rev, 
                  
@role, 
                  
@sel:selid, 
                  
@typeof, 
                  
@xml:base, 
                  
@xml:id, 
                  
@xml:lang and 
                  
@xml:space 
               
               one or more of 
                  
                  a choice of either one of the 14 elements: 
char, 
emph, 
its:ruby, 
object, 
pagebreak, 
span, 
ssml:break, 
ssml:phoneme, 
ssml:prosody, 
ssml:say-as, 
ssml:sub, 
ssml:token, 
sub or 
sup 
                     or text
end of choice 
                  
                
               Note that in addition to restrictions presented in the content model  above, 
                  					use of this element must also respect the following requirement:
                  
                     - The 
                        
lnum element must neither be empty nor contain only whitespace.
                        
                      
                  
                  Such requirements take precedence over any conflicting statements in the
                     						content model or in the lists above of allowed children and parents.