Series-specific level
For a book that is a graded Reader in some series, capture a value in a custom-meta element to indicate its level.
/book/book-meta/custom-meta-group/custom-meta
Capture a meta-name element containing the value
series-specific-level
. Include a second child element
meta-value containing the suitable value among those
supplied by OUP.
<custom-meta-group>
<custom-meta>
<meta-name>series-specific-level</meta-name>
<meta-value>5</meta-value>
</custom-meta>
</custom-meta-group>