[Serialization] IBM-SE-004: XML Output Method

Serialization Section 4, "XML Output Method": The first paragraph states 
that serialization produces either an XML document entity or an external 
general parsed entity. No indication is given about how the serialization 
process chooses between these alternatives. The normalization rules in 
Section 2 always reduce the data model instance to exactly one document, 
so it is not clear how the second alternative is ever invoked. 

Also in this section, the second paragraph adds nothing that is not 
already said in the first paragraph. It should be deleted.

--Don Chamberlin