Author Notes
Capture notes about contributors in an <author-notes>
        element.
The  <author-notes> element may contain child
                <fn> elements for contributor footnotes or
                <corresp> elements for contributor correspondence notes.
Each <fn> or <corresp> element must have a
                @id attribute which contains a unique identifier for the note which
            is used for linking to the relevant contributor(s) (see Contributor Cross References).
If the <fn> or <corresp> is numbered it
            must contain a <label> containing the relevant label text.
Example
<author-notes>
  <fn id="bk978-0-7503-4926-0ch1fn1">
    <label>*</label>
    <p>Equal contributing authors</p>
  </fn>
  <fn id="bk978-0-7503-4926-0ch1fn2">
    <label>†</label>
    <p>Author to whom any correspondence should be addressed.</p>
  </fn>
</author-notes>