code: Rule IfieldNotes() {
  		return Sequence(String("[N:"),
  				ZeroOrMore(WSP()).suppressNode(),
  				TexTextIfield(),
  				String("]"))
  			.label(IfieldNotes);
  	}
docs: ifield-notes ::= %5B.%4E.%3A *WSP tex-text-ifield %5D<p>
  <tt>[N:..]</tt>