Part (group of chapters)

Parts or sections group chapters under a heading. The heading is usually numbered, and there is often a label for the number as well (e.g. Part II, Part A, Section A). Capture parts or sections that group chapters using the part element.

Typecodes used to identify parts

PN	Part number
PT	Part title
PST	Part subtitle
PA	Part author
PTX	Part text (part front matter)
SN	Section number (capture as PN)
ST	Section title (capture as PT)

//part

Use the part element to group chapters.
Do not use the section element. Parts and sections must be considered the same and marked with part.
It is possible to have multiple headings above a chapter (i.e. Part 1, Section B, Chapter 1). If this is the case, then nest part elements to create as many levels as are necessary (//part/part/chapter).
Sometimes chapters might be labelled Section or Part. Capture them as chapters with the correct enumerator. Do not capture these as parts or sections.
A part must have at least one chapter descendant.