Unclassified
Where it is not possible to identify the class of a bibItem, mark it as bibItem class='unclassified'..
The classification of 'unclassified' is used specifically for bibItems where there is no core equivalent, so that a bibItem in a list of other bibItems may still be identified as a bibliographic reference (and not as a p within a bibList).
In a Generic, non-product XML workflow class='unclassified' must be used on all bibItem elements. It is not necessary to do further classification for Generic XML.