Part introductions (ORR)
For ORR, capture a part introduction in a partFrontMatter group or as an individual entry e element.
If one of the following typecodes is used, capture the introduction in an entry e element:
| CN | Chapter number |
| CT | Chapter title |
| CST | Chapter subtitle |
| CA | Chapter authors |
| CO1 | Chapter outline, first level (chapter opening) |
| CO2 | Chapter outline, second level (chapter opening) |
Otherwise capture the introduction in a partFrontMatter element.